This handbook is for guidance only. It was developed by the DoD with the assistance of the military departments, federal agencies, and industry and replaces in their entirety Military Handbooks 470 and 471. This handbook provides guidance to maintainability managers and engineers in developing and implementing a sound maintainability program for all types of products. Maintainability is a discipline that has become more important over the past 30 years as military systems became more complex,costs increased, and defense budgets decreased.