Figure - available from: Journal of Industrial Ecology
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Data on sales and ownership (per dwelling) by appliance type. Dashed lines mark the ownership of 0.5 and 1.0 appliances per dwelling. Underlying data for this figure can be found in Supporting Information S2.
Source publication
Longer lifetimes of consumer products are promoted as an element of sustainable consumption, yet there is a widespread notion that lifetimes are currently in decline, often attributed to planned obsolescence or throwaway mentality. However, empirical evidence is inconclusive and often subject to high uncertainties. Here, we explore long‐term trends...
Citations
... Product lifetime can be defined as ending at the point in time when the product becomes obsolete, i.e. "falls into disuse" (Cooper 2010). Multiple technical, economic, social and psychological factors explain this obsolescence (Krych and Pettersen 2025;Richter et al. 2024). This article makes the distinction between product lifetime, defined as a time period, and product obsolescence, defined as the reason for the lifetime to be ended. ...
... due to the influence of user practices on product obsolescence (e.g. frequency of use, maintenance and aesthetic preferences) (Krych and Pettersen 2025;Richter et al. 2024) and the lack of information on the change of user practices over time after introducing lifetime extension strategies, careful consideration of this variable in sensitivity analysis is called for. These recommendations are in line with the call from Cottafava et al. (2024) for systematic breakeven analysis and transparent reporting of key variables, including the return rate for reuse and the packaging lifetime to ensure the reliability and comparability of LCA studies comparing single-use and reusable packaging. ...
Purpose
Product lifetime is central to circular strategies that by lifetime extension could increase products’ environmental performance. In life cycle assessment (LCA), little attention has been paid to product lifetime modelling, although the environmental benefit of lifetime extension can vary greatly with lifetime values. Since product lifetime modelling may have a significant effect on the results, this study identifies and explains existing approaches. The consolidation of methodology for lifetime extension in LCA can support practice as well as further development of methodology.
Methods
A scoping literature review identified 67 LCA studies of lifetime extension containing 95 cases. The analysis focused on the case description of product lifetime and its integration in LCA calculations. Then, an overview of product lifetime modelling approaches and guidance for selecting them were developed and summarised into a product lifetime modelling framework which follows LCA methodological steps.
Results and discussion
Lifetime modelling differs in terms of (1) the lifetime definition, specifying in the goal and scope definition whether periods of idleness and the full technical lifetime are included, (2) the lifetime integration in equations either using a single value, no fixed value or distribution over a population in the inventory analysis and impact assessment and (3) the lifetime sensitivity analysis during interpretation. However, unclear descriptions of lifetime definition and missing references to lifetime data sources in 63 and 26% of the cases, respectively, show that reporting of product lifetime modelling is insufficient for unambiguous interpretation of the results. Additionally, significant variations in LCA results observed through lifetime sensitivity analysis underscore the importance of product lifetime modelling in LCA of lifetime extension.
Conclusions
Product lifetime modelling is not straightforward, as evidenced by the variety of definitions and existing approaches. The developed lifetime modelling framework offers LCA practitioners a more informed and structured approach to modelling lifetime extension in LCA, highlighting the importance of clear methodology requirements and further development.
Recommendations
Given the significance of product lifetime for LCA of lifetime extension, along with the observed inconsistencies and often insufficient reporting practices, LCA practitioners are encouraged to carefully consider the definition, integration in equations and sensitivity of product lifetime and to report these aspects transparently. The new framework can support these considerations.
... Historical perspectives on this relationship in different contexts and product types are very valuable. Krych et al. (2025) suggest a way of studying this. Research of this kind should be applied specifically to different product types, periods, and locations to account for variation in behavioural and contextual factors. ...
... Even products of similar configuration may be subject to differences in how the flow through or accumulate in the stock of households, and in how the industry leads with production orders. For instance, Krych and Pettersen (2025) studied the sales and ownership of six large household appliances since their introduction in Norwegian households and found that a significant lifetime decrease was experienced only by ovens and washing machines (around the 1990-2000s). They explain the cause of such decrease through specific contextual reasons, namely changes in washing habits for washing machines, and the integration of kitchens in social areas for ovens. ...
Consumer goods environmental policy is increasingly focusing on product durability and product lifetimeextension (PLE) to reduce their impact. Given the growing societal relevance of PLE, this review investigates thediscourse about its environmental effects, and the empirical knowledge that substantiates this discourse. Onehundred and nine relevant articles were selected from 388 distinctive records identified in two databases, Scopusand Web of Science. The statements about the environmental effects of PLE in these publications were extractedand analysed, and a detailed process of backward citation tracking was followed to identify the empirical basesubstantiating these statements, leading to 85 additional publications that were included in further analyses.The findings show that the main environmental benefits expected from PLE are related to reductions in thevolume of goods produced, which result from expected reductions in demand due to delayed product replace-ment. However, this reasoning is based on two under-researched assumptions about consumer and industrybehaviours: that the demand for new products is driven by replacement, and that decisions on production vol-umes in the industry are driven by consumer demand. The empirical base in the field is dominated by quanti-tative assessments that reproduce these assumptions rather than studying them. The findings from a handful offield studies that investigate the presumed behaviour, question that it applies. Therefore, a research agenda isproposed to better understand the relations between product lifetimes and material flows and the influence ofconsumer and industry behaviour over them. Moreover, given the current gap between the durability discourse and the empirical knowledge that would be needed to substantiate it, recommendations are made for academics, policy makers, advocacy groups, and businesses environmental strategists to moderate their expectations from product longevity measures.
