A note on block and bad‐as‐old renewal of components with limited system time horizon

As the time to dispose of a system approaches, renewal of wearing components becomes progressively less attractive. The traditional optimization method for this situation is through net present value and dynamic programming. Presents a much simpler solution for rapidly‐wearing components founded on finding the optimum number of equal renewal intervals. Unequal intervals increase expected failures for any fixed number of intervals, and it is argued that it is unnecessary to discount costs. The model can be used with either the Cox renewal function or the cumulative hazard function representing the expected number of failures between scheduled renewals of the component, the choice depending on whether the component is minimally repaired or renewed at these failures.