In this period of diminishing Department of Defense (DoD) budgets, an increasing percentage of each budget goes to the operating and support (O & S) accounts. This slows modernization of weapons inventories and could cause the average age of weapon systems in use to rise, perhaps to unacceptable levels. To address this situation, decision makers must buy fewer or less expensive replacement systems and find ways to lower the O & S costs of existing and future systems. Concerned about the effect of shrinking modernization budgets, the Under Secretary of Defense for Acquisition and Technology recently asked the Service Acquisition Executives to look for acceptable ways to minimize O & S requirements for systems now under development. He also asked that a study be undertaken to determine if past efforts to reduce O & S costs have been effective. This study responds to that tasking.