Most of the DOD budget is spent on the day-to-day tasks necessary to make sure every existing U.S. weapon system continues to work properly. While the DOD dedicates a significant amount of money to the research and development of state-of-the-art technologies, this accounts for only a small portion of the yearly budget. According to the DOD’s fiscal year 2024 budget request, the federal government spends more than $400 billion per year on operations, maintenance, and personnel necessary to ensure that DOD weapon systems are combat ready and mission capable.

Sustainment is every part of the logistics ecosystem working together to ensure each platform is ready to perform its mission. It encompasses logistics and personnel services to maintain operations until mission accomplishment and subsequent redeployment of the force. Sustainment includes training, testing, upgrading and procuring parts.