The phenomenon of premature obsolescence of products relates to the fact that products do not last as long as they should or could. There are nowadays growing and widespread suspicions about the diminishing lifetime of consumer products. An increasing number of empirical studies confirm these suspicions, at least for certain goods. Various types of premature obsolescence are omnipresent in our daily life. For example, some products become materially obsolete due to the impossibility of disassembling them, while other still functioning products are too early discarded because they are no longer attractive or satisfying in consumers’ eyes. Premature obsolescence has huge drawbacks, for consumers as well as for the environment, and, on balance, the potential positive side effects do not outweigh these drawbacks. The willingness to promote more sustainable production and consumption has led to major legal developments and proposals at the EU and national level over the past years. However, new rules tackling premature obsolescence are highly fragmented, across different legislators (EU, national, regional), legal fields (product legislation, consumer law, waste law) and types of rules (general / specific, etc.). This legal fragmentation creates risks of overlaps, gaps and conflicts. Therefore, this doctoral research addresses the central question how EU and national legal rules currently tackle premature obsolescence and how, if necessary, the legal framework could be improved. In the first chapter, the thesis extends knowledge on premature obsolescence and offers concepts and corresponding definitions that lawmakers should use when regulating the issue. Among these are the concepts of ‘product lifetime’, ‘product sustainability’, 'durability', 'maintenance', 'upgrades', 'direct reuse', 'repair', 'refurbishment' and 'remanufacturing'. The following chapters identify and evaluate, for every stage of the product lifecycle, the panoply of rules adopted by the EU and in the selected Member States (Belgium, France and Germany) to promote product sustainability. These rules include ecodesign legislation (chapter 2), rules regulating the disclosure of product sustainability information (chapter 3), guarantee rules (chapter 4) and waste rules (chapter 5). Alongside this legal analysis, the thesis makes a normative contribution, proposing concrete amendments to existing legal texts and more general policy recommendations to prolong product lifetime. In general, the thesis clearly shows that a wide web of legal instruments exists to combat premature obsolescence, but that (transparent) connections between them are lacking. The thesis advocates considering this panoply of rules (preventive/coercive, product-/consumer-oriented, self-regulatory/legislative) as a toolbox to deal with this complex issue and ensuring that the legal framework remains consistent and coherent. The thesis also confirms the necessity of prioritising rules at the EU level, while leaving some freedom to the Member States. Finally, the thesis highlights that both consumers and businesses should be seen as agents of change, with their decisions and actions guided by the common long-term objective of environmental protection.