Failure rate curves of many deteriorating systems are typically bathtub shaped. Bathtub failure curves based on failure rate functions show three distinct phases namely, infant mortality period, useful period, and wear out period. Existing reliability models have been developed purely from the consumer or manufacturer’s perspective thereby delinking the third phase from the first two phases. The objective of the present work is to discuss several optimality issues based on the total average cost of the system over its entire useful life that encompasses the cost incurred on the system by the consumer as well as the manufacturer.