This chapter suggests how to use these maintenance concepts in the maintenance setting as well as how to modify them to fit the post-maintenance era. Preventive maintenance (PM) is the first major scientific approach to equipment management and started in the 1950s in the United States. The major components of a PM program are PM schedule and PM task list. A sufficient PM workforce with necessary skills is essential to the success of a PM program. PM tasks often require equipment and tools, from common mechanical hand tools, to sophisticated electronic scopes, and to custom-made devices. Similar to PM equipment and tools, required PM materials and parts must be readily accessible before a PM starts. Reliability-centered maintenance was developed by aircraftmanufacturers, airlines, and government agencies in the productive maintenance phase when the reliability of the equipment became a key focus and safety was a primary consideration.