OPTIMUM REPLACEMENT POLICIES FOR A USED UNIT

In many situations, it may be more economical to use a used unit than to do a new one. This paper considers an age replacement policy and a periodic replacement policy with minimal repair at failure for a used unit of age x. We discuss optimum replacement policies which minimize the expected cost rates for a specified age x. Further, we obtain an upper bound of an optimum time for an age replacement model and an optimum age of a used unit for a periodic replacement model when the replacement time is previously specified.