Warranty costs for repairable products with a two-attribute policy: impact of warranty execution

A warranty policy involving two attributes, for example time and usage, is considered. Usage is assumed to be related to time through the usage rate, considered to be a random variable satisfying a specified probability distribution. The paper analyses a policy where the product is repaired on failure within the specified parameters but warranty is not renewed. The failure distribution of the repaired items is assumed to be different from the failure distribution of new items. Furthermore, the situation that warranty may not be executed all the time is incorporated. Consumer behaviour is modelled through a warranty execution function.