Global textile production and consumption has increased steadily over the past 15 years, which has caused significant impacts on the climate and the environment. In 2022, the EU launched a strategy for sustainable and circular textiles, stating that extending the life of textile products is the most efficient way to reduce their impact on the climate and the environment. Shell jackets for outdoor use are textile products that are frequently discarded by their first users and re-sold on the second-hand market. This study evaluates the performance of 16 second-hand shell jackets from three second-hand stores in Sweden via material testing of four key functional aspects. Comparing the results with the jackets’ original performance, this study describes the change in functionality over time. The results indicate that air permeability does not change significantly, whereas water repellency, water penetration resistance, and breathability decrease over time, although they do so at different rates. With the aim of promoting circularity and encouraging longer product use, this study also compares the price evolution of jackets with their functionality over time. The results reveal that the resale price of the jackets is lower than could be expected based on the level of remaining functionality in the jackets.