Using the case of outdoor shell jackets, this research studies obsolescence and potential lifespan extension by re-examining how product functionality, objectively and subjectively, develops over the course of product lifespans. In particular, the study focuses on second-hand stores for outdoor products. Functionality is indicated by user perceptions, visual assessments, laboratory measurements and price data, collected at first use, second-hand resale and end-of-life. Perceived functionality and price decline more rapidly (5–6 % per year) than assessed and measured functionality (around 3 % per year). This could be explained by properties related to appearance, which are not assessed nor measured but influence user perceptions and price. Discontentment regarding such properties appears more relevant for obsolescence than inadequate performance, suggesting the potential for design for attachment and timeless design. The relative stability of measured functionality over time suggests that a barrier for second-hand sales, concern about performance, could be ameliorated by a potential functionality-label.

中文翻译：

---

二手贝壳夹克是否比用户想象的要好？整个生命周期中感知、评估和测量功能的比较

本研究以户外冲锋衣为例，通过重新审视产品功能在产品生命周期中客观和主观的发展情况，研究过时和潜在的生命周期延长。该研究特别关注户外用品的二手店。功能通过用户感知、视觉评估、实验室测量和价格数据来表明，这些数据在首次使用、二手转售和报废时收集。感知功能和价格下降速度（每年 5-6%）比评估和测量功能（每年约 3%）下降得更快。这可以通过与外观相关的属性来解释，这些属性未经评估或测量，但会影响用户的感知和价格。对这些特性的不满似乎与过时比性能不足更相关，这表明附件设计和永恒设计的潜力。随着时间的推移，测量的功能的相对稳定性表明，潜在的功能标签可以改善二手销售的障碍，即对性能的担忧。