Lifestyles of enough exploring sufficiency-oriented consumption behavior from a social practice theory perspective

Maren I Kropfeld, Department of Business Administration, Economics and Law, Carl von Ossietzky University of Oldenburg, Ammerländer Heerstr. 114-118, 26129, Oldenburg, 26129, Germany.

Email: maren.ingrid.kropfeld@uol.de

So far, most sustainability initiatives have focused on upstream approaches such as eco-efficiency, slowing down the negative impacts of our current production and consumption systems to some extent. However, efficiency gains are often offset by rebound scaling and

growth effects: higher efficiency leads to lower prices and consequently incentivizes increased consumption (Polimeni et al., 2008; Santarius, 2016). As the targets in the Paris Agreement require a complete phase out, efficiency strategies alone will not deliver the required reductions (Alfredsson et al., 2018). Even a consistency approach, in which materials are continually recycled and reused to limit demand for new materials, can lead to increased resource consumption if the total consumption of products and services is not moderated (Bocken and Short, 2020). A successful circular economy could be achieved if the total global demand for products and resources stabilized, which so far is a utopian idea in our growth-based economic systems and increasing global population (ibid).

Only if we combine efficiency and consistency measures with strategies to lower the absolute level of consumption, we will be able to sufficiently lower our emissions and resource consumption (Leng et al., 2016; Spangenberg and Lorek, 2019). Recent research has shown that options reducing overall consumption levels have higher mitigation potentials in domains such as transport, services, and clothing than green consumption measures, while green consumption options show more effective reductions in the domains of food and manufactured products (Vita et al., 2019). So, only a combination of all three strategies will lead us toward sustainable consumption and production systems within the ecological limits of this planet (Vita et al., 2019).

Sufficiency acknowledges basic human needs such as community, shelter, and nutrition, but challenges unnecessary over-consumption (The Royal Society, 2012). Sufficiency also claims to maintain or even improve the quality of life while simultaneously reducing the environmental impact and resource consumption (Persson and Klintman, 2021), which adds a qualitative dimension to the concept and thus distinguishes it from efficiency and consistency strategies. Sufficiency aims at well-being beyond materialism by paying attention to different, non-material, aspects of a good life (ibid). Especially from a social justice perspective, sufficiency does only address a maximum ecological allowance, but also includes a minimum level of consumption to ensure a decent life for everyone (Fuchs et al., 2021).

The concept of sufficiency is reciprocally related to the ideas of a post-growth or degrowth economy (Reichel and Albiez, 2016) or Daly's (1991) steady-state economy. It addresses the sustainable consumption corridors suggested by Di Giulio and Fuchs (2014), who call for a definition of a minimum and maximum standard of consumption—an idea also represented in the concept of the Doughnut Economy by Kate Raworth (2017). While the sufficiency-related discourse on these economic concepts is situated on the macro-level, the focus of this paper lies on the micro-level perspective of sufficiency: consumer behavior and lifestyles within certain consumption corridors.

Promoting individual sufficiency is difficult and has so far not rendered satisfactory results, as our consumption behavior depends on culture, society, and the environment (Grunwald, 2015; Speck, 2016) and cognitive factors are only partly able to predict actual behavior (Gatersleben et al., 2002; Stancu et al., 2016). Theories such as the theory of planned behavior "suitably describe situations of intentional and reflected behavior"

(Spangenberg and Lorek, 2019: 1073). However, people do not always consciously reflect their actions and choices, nor have they all the information available that would be necessary to do so (Klein and O'Brien, 2018). There is a reported gap between pro-environmental attitudes and values, and actually performed behavior that is not always in harmony with these values (Blake, 1999).

Consumer education, focusing on changing attitudes and beliefs, will not be enough to support more sustainable consumer behavior, as our patterns of consumption are embedded within social practices (Hargreaves, 2011; Warde, 2005). Practitioners and policy makers have to offer consumers attractive, more sustainable alternatives to their daily practices (Southerton et al., 2004). If sufficiency is to be established in peoples' everyday lives, the respective concepts, and recommendations for action must be located on the level of social practices (Speck, 2016).

A social-practice theoretical (SPT) approach broadens the perspective on human behavior by focusing on ritualized, everyday behavior, which is repeated without specific reflection (Kumar and Kumar, 2008). It includes factors beyond the control of individuals such as infrastructures or social norms (Evans et al., 2012). While SPT is no catch-all-theory, it enables a sociological and contextual approach to consumption behavior and lifestyles (Spaargaren, 2003) and provides fresh insights into the basis of human behavior and its transformation over time (Davies et al., 2014).

SPT can help to understand changes in consumption patterns as "the sources of changed behavior lie in the development of practices themselves." (Warde 2005: 140) It is open to an analysis of related practices, links between practices or their elements, and the dynamics between those elements and makes it therefore useful in the research area of changes toward more sustainable behavior (Spotswood et al., 2015). While most practices involve the acquisition and use of goods and services, consumption as such is seldom meaningful. Rather than being a purpose, consumption is an inherent part of everyday practices (Røpke, 2009).

According to Reckwitz (2002: 249) a practice is a "routinized type of behavior which consists of several elements, interconnected to one other: forms of bodily activities, forms of mental activities, 'things' and their use, a background knowledge in the form of understanding, know-how, states of emotion and motivational knowledge." Shove et al. (2012) offer a simplified, and thus easier to operationalize, definition of a social practice focusing on the three central elements (cf. Figure 1): materials including objects, infrastructures, tools, and the human body; competences incorporating know-how, practical knowledge, skills, and a shared understanding of appropriate behavior (e.g., social norms); and meanings in the sense of the symbolic significance of activities.

Rules as a fourth dimension of social practices have so far not been taken up by most scholars. Gram-Hanssen (2010: 155) criticizes that the element “competences” is “overly simple, as the authors do not distinguish between [...] know-how or non-verbal knowledge and explicit, rule-based, or theoretical knowledge”. Other perspectives suggest that rules are part of the material or the competence dimension. The importance of rules should, however, be considered in an analysis of consumption practices (Giddens, 1984; Warde, 2005). In this paper, I consider rules as formal, institutionalized, and explicit rules (Gram-Hanssen, 2010). Informal rules are accounted for by the dimensions of know-how, and/or meaning, depending on the context.

Sufficiency aims at changing peoples’ lifestyles. Lifestyles represent the way we live, spend our time, interact with others, indicate where we live, where we shop, and what we consume (Backhaus et al., 2012). Lifestyles can be understood as a combination of everyday practices related to various aspects of life such as nutrition, mobility, and leisure activities (Spaargaren, 2003; Warde, 2005). They are also an expression of ones’ attitudes and values and require certain competences (Leng et al., 2016). So far, there is not one single definition for sufficiency lifestyles (Spangenberg and Lorek, 2019). For this paper, the following understanding is adapted: Sufficiency lifestyles aim at a reduction of overall consumption levels to reduce negative environmental impacts (Spangenberg and Lorek, 2019).

As sufficiency is not a technology-related sustainability strategy, but inherently dependent on changes in our consumption behavior, we call it a behavior-based sustainability strategy. Sandberg (2021) offers a typology of the four types of sufficiency-related consumption changes on an individual level:

Shifting consumption practices toward more sufficiency-oriented ones is essential in many areas of our lives. In the following section, a configurative literature review is developed to aggregate the elements of sufficiency-oriented practices, focusing on the so far underrepresented areas as identified by Sandberg (2021).

Configurative literature reviews can serve to generate or explore theory, configure synthesis of or identify patterns within a topic, and value study contributions or emergent concepts (Gough et al., 2012). (Systematic) literature reviews can help practitioners addressing managerial issues, as well as scholars, by highlighting opportunities for further research (Briner and Denyer, 2012). Methods from full systematic and traditional configurative literature reviews are used for this study to collect insights on the elements

of sufficiency consumer practices and to identify commonalities (Gough et al., 2012; Haddaway et al., 2015).

The literature study was designed along the steps for systematic reviews according to the Collaboration for Environmental Evidence (2013). Starting from the research question, relevant search strings were defined by testing various search strings on a sample database (SCOPUS). As the German search strings did not render any relevant results at this stage, only English search strings were used for the literature search.

The most relevant search string across all databases (SCOPUS, Web of Science, and Google) was:

TITLE-ABS-KEY (( sufficiency OR sustainability OR ( consumption AND reduction ) AND ("social practice theory" OR praxeology OR "social practice*")) AND (LIMIT-TO ( DOCTYPE, "ar") OR LIMIT-TO (DOCTYPE, "cp") OR LIMIT-TO (DOCTYPE, "ch") AND (LIMIT-TO ( LANGUAGE, "English"))

Following Gossen et al. (2019), another search string has used including literature and concepts related to sufficiency-oriented behavior:

TITLE-ABS-KEY (( "social practice theory" OR "social practie*")) AND (sustain* OR green* OR ecolog* OR environment*) AND (sufficien* OR reduc* OR conscious* OR mindful* OR frugal* OR anti*consum* OR slow* OR simpli* OR down*shift* OR ethical OR responsible) AND (consum* OR behavio* OR lifestyle*) AND NOT (energy OR housing OR food OR nutrition OR mobility) ) AND (LIMIT-TO ( DOCTYPE, "ar") OR LIMIT-TO (DOCTYPE, "cp") OR LIMIT-TO (DOCTYPE, "ch") ) AND (LIMIT-TO ( LANGUAGE, "English"))

A systematic search of online literature databases (SCOPUS, Web of Science) and the world-wide web (Google) was conducted in February 2021. All articles were examined for their relevance for the review question along the following a priori inclusion criteria (cf. Figure 2). Duplicates were removed and grey literature was included in the analysis to avoid publication bias.

After screening the resulting papers from the literature search, relevant practices were extracted from these studies. Practices included in the further analysis had to fulfill the following criteria:

The practices were transferred to and a table (cf. Table 2), where they were sorted along Sandberg's (2021) four categories of sufficiency-related consumption changes. Multiple practices and the elements found by the authors of the studies were aggregated along the elements of social practices (materials, competences, rules, and meanings). As seven of the nine identified practices relate to clothing consumption, the deep analysis of the practices' elements and the following discussion section focus on sufficiency-oriented clothing consumption. Although, this was not the initially intended goal of this study, a focus on sufficiency strategies for clothing consumption makes sense: The textile and clothing industry has experienced extensive growth in the last decades and has become one of the largest and most polluting industries worldwide (Ellen MacArthur Foundation, 2017). Its impact is not only on CO2 emissions but also on water and land use, the use of chemicals, and social concerns such as unsafe and unhealthy working conditions, child labor, and low wages (ibid). Therefore, Niinimäki et al. (2020) call for fundamental

changes in the fashion business model, which include, for example, a shift in consumer behavior toward a decreased clothing purchasing and extended garment lifetimes.

In terms of generalizability, the findings of the studies do of course not provide a generalizable truth valid for all practices, countries, and cultures. They rather act as guidance showing tendencies for certain practices and parts of a population (Schanes et al., 2018). In the papers analyzed, most of primary data referred to consumers living in cities in English-speaking countries of the Global North, namely, Middle-Europe, North America, and Australia¹. Most authors selected their study subjects from diverse income and age groups with different jobs. Some authors used their personal network and snowball techniques for recruitment, resulting in a sample that was mainly white academics. All papers used qualitative methods such as in-depth or semi-structured interviews to gather data (cf. Table 1). Observations and case studies were also represented among the selected studies. Most of the informants were conscious consumers, activists, or otherwise citizens already engaged in sustainable consumption practices. Some studies also looked specifically at intentional green, eco-, or cohousing communities, which hardly represent the public but are interesting cases to look at sufficiency-in-practice.

Nine main practices are described in the papers, seven of them relating to clothing consumption practices, the other two to general household items or food (cf. Table 2). The practices described in the studies were sorted along Sandberg's (2021) categories of sufficiency-related consumption changes and materials, competences, rules, and meanings summarized for each practice. As most of the practices relate to clothing consumption, the following analysis also mainly represents the elements of sufficiency-oriented clothing consumption.

Materials. The variation of materials is as wide as the range of practices. Every practice demands its own specific infrastructures, tools, and materials. Generalizing the categories into which the materials fall, we can see that high quality, sustainable materials are a basis for consumption practices that aim at absolute reductions or modal shifts. Consumers

engaging in modal shifts of consumption practices toward buying second hand, DIY, rental services, or green purchasing make use of mobile applications to get information about products and use electronic payments to book services. The latter mostly applies to young citizens of the Global North, while the study in Southeast Asia by Retamal (2019) showed that most service providers there use a hybrid solution of both physical storefront and digital presence.

Upcycling and repairing practices to prolong product lifetimes did, of course, include the materials or fabrics to be upcycled or repaired, but it was also found that most people engaging in these practices did not use sophisticated or specialized tools for upcycling or repairing things in their everyday life. Rather, they were more likely to engage in repairing practices if they did not need more than their body and hands or simple household tools to complete them (Wakkary et al., 2013). Only when placed into a workshop-situation and provided with more specialized tools did people also use them. For that, not only body and tools were essential but also the space to host the workshop or to provide a repairing room (McEachern et al., 2020)

These spaces could be both public or private and were also required for the next category of sharing practices: clothes swapping was found to be the predominant sharing activity, both professionally and privately organized (Callmer, 2019; Camacho-Otero et al., 2020; Daly, 2015; Perera et al., 2018). One study (Camacho-Otero et al., 2020) found tokens used as currency material for their clothes swapping events, while the others used principles like one-for-one or relied on the fairness of their participants.

Competences. In terms of competences and skills, some reoccurring elements could be found across various practices, for example, being able to critically reflect one's own consumption behavior and the knowledge about the environmental impact of consumption and more specifically, the textile industry in the case of clothing-related practices (Callmer, 2019; Camacho-Otero et al., 2020; Daly, 2015). All DIY, upcycling and repairing related practices were based on the practitioners' ability to create a vision for their project, to recognize the potential of various materials and know how to transform or reconstruct them (McEachern et al., 2020; Wakkary et al., 2013). An essential enabler for these practices were online tutorials on blogs or social media from people sharing their ideas, projects, and experiences and from which the informants of the studies analyzed here were willing to learn. Rental or sharing services also involve a certain level of social trust and skills for operating and carefully treating objects that one does not own (Retamal, 2019).

Meanings. Meanings such as environmental concern, demonstrating a certain social status or belongingness to a certain community, saving money and the desire for a simpler life keep reappearing throughout the practices. The meanings attached to practices of an absolute consumption reduction, such as the Buy Nothing Year, are based on an awareness of the environmental and social consequences of one's consumption habits and the resulting bad conscience (Callmer, 2019). But also, more personal aspects did motivate people to take part in the Buy Nothing Year, such as the desire for a better control

over their strained finances, more flexibility in terms of worktime if they need less money for consumption and even a feeling of “consumption fatigue” and the desire to “de-colonize” oneself from consumption to increase one’s personal well-being. Similar meanings were attached to decluttering one’s home, which sometimes served as a first step toward a less consumption-intensive lifestyle (Callmer, 2019).

Modal shifts in consumption as well as practices to prolong product lifetime and sharing practices were also motivated by an increased awareness of the impact of our consumption behavior on the world and the wish to live in a healthier environment, but also a personal desire for simplicity and thereby saving money, the wish to express one’s sustainable identity, and lastly, the wish and enjoyment to be part of a community (e.g., Camacho-Otero et al., 2020). In the case of the upcycling or repairing workshops, people enjoyed the handcraft skills they acquired, and the creativity involved, but also highlighted the enjoyment of the social aspect of being part of a group of like-minded people and to do something collaboratively. The latter aspect is also connected to clothe-swapping events, which were perceived as a fun activity with like-minded people that also fulfilled the wish for novelty. Interestingly, using (rental) services was mainly motivated by space and time pressures, saving money and a desire for access to a greater variety of goods and goods one could else not afford and thus fall somewhat outside the typical meanings connected to sufficiency-oriented consumption practices (Retamal, 2019).

Rules. Finally, the fourth element of social practices, rules, was only taken up by three studies (Callmer, 2019; Camacho-Otero et al., 2020; Retamal, 2019). There, they were connected to using rental and sharing services, which require a certain legal framework or formal institutional provision for the businesses providing those services (Retamal, 2019); rules for clothe-swapping events, that is, which clothes to bring and how to behave at the event or solve conflicts (Camacho-Otero et al., 2020), and the process of decluttering following the KonMari method (Callmer, 2019).

Analyzing the practices from this paper’s literature review, several examples for the importance of addressing more than peoples’ attitudes when aiming at changing consumption behavior could be found. In case of materials, repairing tools, high-quality products, or infrastructures such as public spaces for workshops or clothes-swapping events were the basis for sufficiency-oriented practices. This is in line with the work by Watson and Shove (2008) on the recursive relation between products, projects, and practices, where they point out that (i) materials are essential elements for every practice and have a huge influence on the practice, and other elements of the practice, and (ii) competence is embedded in and distributed between tools, materials, and people (Watson and Shove, 2008).

Competences and skills are especially important for practices related to product longevity and sharing. Community workshops or online blogs with peer-to-peer learning

are platforms used to acquire the skills and know-how necessary for these practices. These learning and DIY processes take time, of course, which some consumers might not feel they have to spare. This supports the idea of re-imagining how we want to live, work, and how to spend our time to live a good live, which is taken up by the post-growth discourse (Reichel and Perey, 2018). For absolute reductions or modal shifts in consumption, personal reflection, and knowledge of the impact of consumption was more important. This requires consumer education and transparent communication and critical marketing measures such as sufficiency-promoting marketing by the manufacturers so consumers can make an educated decision (Gossen et al., 2019).

Finally, the meanings attached to sufficiency-oriented consumption practices go way beyond altruistic motives like environmental concern. As a study by Kropfeld et al. (2018) showed, environmentally concerned consumers (with more altruistic motives) have a higher environmental impact than voluntary simplifiers (with more self-related motives). Personal or egocentric motives, therefore, can lead to sufficiency-oriented behavior, as the example for sharing services from this review showed. This is in line with Sandberg's (2021) findings on sufficiency practices related to miscellaneous consumption, as she connects a reduction of consumption of various products (incl. clothing) to anti-consumption lifestyles such as voluntary simplicity or frugality.

Extending lifespans and sharing of various products were the most dominant strategies in this study. As also Sandberg (2021) notes, absolute reductions are not always possible or desirable. Rather, modal shifts and sharing practices may be practical ways to change unsustainable consumption patterns. In the case of clothing, repairing, and swapping extends the lifespan and use phase of these products, which in turn should reduce the need for new garments. The focus on clothing consumption has already been noted by Sandberg (2021) and is also evident in the findings of this study. Extending product lifespans is a key sustainability strategy, especially for sufficiency-oriented businesses in the textile and clothing industry (Gossen and Kropfeld, 2022). Although the sharing economy has gained increasing attention during the last years, it does not automatically contribute to sufficiency (Frenken and Schor, 2017; Sandberg, 2021). Rather, we must combine consistency and sufficiency strategies (Bocken and Short, 2020), assess the effects of sharing practices on a case-to-case basis (Sandberg, 2021), considering possible rebound effects (Reimers et al., 2021).

Provided with the right materials, skills, and by addressing related meanings and concepts, sufficiency-oriented practices can be an attractive alternative to mainstream consumption behavior. Still, it often costs more time to engage in these practices, which might hinder consumers from taking up these practices.

Implications for sufficiency-supporting policies. Heiskanen et al. (2018) and Spangenberg and Lorek (2019) point out that due to the variations across sufficiency practices, as well as differences between urban and rural consumers and between countries, setting a joint compass for sufficiency policies is unpractical. Nevertheless, two main issues are addressed here that are important when talking about sufficiency-oriented consumption, and the role of policy makers in supporting resource-light lifestyles.

Firstly, the findings of this study support that sustainable behavior is embedded in practices and dependent not only on peoples' mindsets, but also on their know-how, skills, and the infrastructure and things surrounding them. This consorts with Schäfer et al.'s (2018) recommendation of shifting problem framings from technical innovation and individual behavior to a practice-oriented approach and with Spangenberg and Lorek (2019) pointing toward the limited effectiveness of most current consumer policies due to their narrow focus on consumer behavior determinants like rational arguments. As practices emerge in rather unforeseen ways, it is impossible to precisely steer their development (Shove and Walker, 2010). Institutions could support the introduction of new practices or change existing consumer practices by providing enabling or more favorable conditions.

Secondly, as environmental concern is not the only meaning attached to sufficiency consumer practices, other motivations and concerns should be considered in the development and promotion of new products or policy measures. These can address the desire to save money and time, to live a healthier lifestyle, or to be part of a community (Leng et al., 2016). A sufficiency-oriented social and institutional framework can accelerate sufficiency practices in becoming mainstream (Spangenberg and Lorek, 2019). However, the measures taken should not be one-time events only, but provide the space and opportunity for long-term regular exchange about practices and experiences (Heiskanen et al., 2018).

Implications for sufficiency-oriented business models. In addition to the insights on the policy level, businesses as the providers of new products and services can influence a shift toward more sufficiency-oriented practices. The value proposition, for instance, does not have to refer to environmental concern only but can also address other meanings such as saving money or staying healthy. The desire of wanting to belong to a community can be used by companies to bring people together and help them to motivate and learn from each other.

In the value creation process businesses can support the competences needed for sufficiency practices, such as educating consumers about the environmental impact of consumption or teaching them repairing skills. This finding is in line with other scholars such as Leng et al. (2016) or Phillips and Waitt (2018), who suggest developing subsistence skills, modular designs, or sharing platforms as factors to support sufficiency lifestyles and practices. Environmental awareness and creativity as central competences for almost all sufficiency practices could be supported by sharing user stories that embed the product or service into the respective practice. Furthermore, retailers and brands can use their shop floor to offer workshops, educational, or swapping events or offer second-hand products.

Changing consumers' behaviors by offering new practices will also make customers part of the value creation process and thus change their role from passive consumers to more active prosumers (Toffler, 1980). Especially value creation for community-based offers or products that require subsistence-related skills cannot happen without the consumers' active contribution. This business-consumer relation is an interesting point of investigation that could not be covered by this study but is a promising avenue for further research.

The value captured might result from more loyal customers, if they feel part of a community, for example, and therefore stay loyal to the company; or from additional benefits created for society and the environment, for example, by educating consumers to use products longer (Giese et al., 2016). This idea is of course already taken up by non-profit organizations and social entrepreneurs. The future of a sustainable business model might well go into this direction and addressing the question whether there can be sustainable financial gains without social and ecological value.

This literature study shows that up to the point of study (February 2021) only few papers have looked at sufficiency consumer practices using SPT in other areas than energy, food, housing, or mobility. Although sufficiency is a behavior-based approach having found a stand in the sustainability discourse and SPT offering a comprehensive framework for the analysis of consumer behavior, the combination of both approaches seems to gain foothold only slowly. Several scholars have emphasized the usefulness of applying SPT to behavioral approaches to sustainability (Corsini et al., 2019) and the studies explored in this paper show that there is more to sufficiency-oriented consumption practices than just an underlying “green attitude”.

The analysis shows that SPT is not a precise analytical tool for human behavior, but rather a holistic heuristic that allows for adaptation and transformation. This of course implies that the boundaries of practices are not always clearly defined or located on the same analytical level. In some cases, practices may describe micro-level human behavior; in other cases, SPT is used to broaden the view on policy implications within a city or region. Aggregating these various views is useful in painting a more holistic picture of sufficiency consumer practices. It includes materials, competences, and meanings on all levels—from personal skills to public infrastructures.

The literature study points toward domains that have not yet been studied from a SPT point of view but might benefit from this approach. Outside of the SPT heuristic, there are many studies in these domains tackling sufficiency consumption behavior. This suggests that more studies in the underrepresented domains can contribute to a more general understanding of sufficiency consumer practices and then also inform policy and practitioners in these fields.

Another critical finding from the literature study is the lack of quantitative studies in the field of sufficiency practices. In the sample presented in this study, only qualitative research has been conducted. Qualitative work helps us to understand new approaches and applications on the small scale and is therefore important in exploring new fields or in gaining deep understandings of certain topics. Gaining reliable data on a bigger scale and moving forward from analyzing single case studies or practices to researching a broader base and dynamics between different phenomena requires quantitative research approaches. Results from quantitative studies can inform practitioners and policy makers on widely applicable measures to support sufficiency practices. If this is compatible with using SPT as an analytical lens, however, would have to be discussed further.

Despite its usefulness, there are several limitations one must bear in mind when conducting, reviewing, and referring to findings of configurative literature reviews: first, the publication bias, which the author has tried to omit by including grey literature in her study (Haddaway et al., 2015). Second, language bias occurs because most of the time, a researcher will only be able to include studies in his or her mother tongue and/or English. In this study, German studies could have been included (as it is the author's mother tongue), but as the German search string did not render any results, only English papers were part of the review. Third, availability, confidentiality, and cost biases might lead to the exclusion of relevant studies. In this review, all papers that resulted from the search were available to the author (Collaboration for Environmental Evidence, 2013). Fourth, familiarity bias can be omitted by including researchers from various fields into the review process. Where a researcher is working on his/her own, as in this study, objectivity cannot be entirely ensured, as the literature will most likely be picked from the own research field and interpreted by the author alone (Collaboration for Environmental Evidence, 2013). The author has attempted to address this bias partly by focusing on practice-related literature and thus relying on the categorization and interpretation of practices of other researchers in their studies. More studies could have been included and more insights aggregated, if also papers were chosen, and contents were coded that did not already rely on the operationalization practice theory offers.

As indicated above, studies that do not explicitly use SPT as heuristic could be included if sufficient resources were available for an extensive coding and interpretation process. Also, non-consumption as the most "sufficient" form of consumption is underrepresented here but should gain more attention in the sustainability discourse as the "ultimate" sustainable form of consumption. Finally, the relevance of the single elements of the respective practice has not been quantified by the studies included in this review. As only few studies were identified, no quantified summary or weighing of elements could be made here.

Maren Ingrid Kropfeld was born in Bamberg, Germany. She studied International Management in Karlsruhe, Berlin, and Paris. She has worked as a freelance editor and lecturer and finished her PhD in Ecological Economics at the University of Oldenburg in 2022.