Damaged durable goods
分析耐用品垄断厂商引入受损品（简化版）的动机，发现这虽能缓解时间不一致问题，但可能降低福利，与静态模型结论相反。
I analyze a durable‐goods monopolist's incentives to introduce a damaged good (a stripped‐down version of the original good) in an infinite‐horizon framework. The damaged good helps the monopolist to mitigate the Coasian time‐inconsistency problem. However, it may lead to a welfare reduction: low‐valuation buyers are induced to purchase the low‐quality damaged good early rather than buy the high‐quality original good later, and when the players are patient the surplus loss from quality reduction outweighs the gain from earlier consumptions. This welfare result contrasts with the previous literature based on a static framework .