Assesses the relationship between tank age and the mission-critical failure rate for the Army's M1 Abrams tank. Budget limits have brought about extensions in the service lives of many Army weapon systems. In the widespread belief that the increases in fleet age will create readiness and cost problems, the Army is executing recapitalization programs to rebuild or upgrade selected weapon systems to retain combat capabilities and hold down maintenance costs. This research assesses the effects of age on mission-critical failure rates for M1 Abrams tanks.