Abstract: In view of the short life of consumer electronic products and the frequent upgrade process, considering that users may replace products in advance under the consideration of multiple factors, some warranty claim manufacturers do not have to bear the cost of quality assurance, which will help manufacturers to improve their profits. Considering the case of random sales, the cost of quality assurance is predicted by integrating hardware failure, software failure, random sales and users' replacement behavior in advance, including the situation where hardware failure and software failure are independent and correlated, the modeling process of quality assurance cost within a fixed time interval is discussed. The numerical analysis shows that the cost of quality assurance can be significantly reduced when users' replacement behavior is taken into account, and it can also provide references for manufacturers to make quality assurance policies.

Key words: warranty cost, users' replacement behavior, hardware and software failure, random sales