The Defense Enrollment Eligibility Reporting System (DEERS) is a database used by the U.S. Department of Defense to manage information about military personnel, their family members, and other eligible individuals. It ensures that those entitled to military benefits, such as healthcare and education, are accurately recorded and can access these services. DEERS is essential for maintaining accurate records and eligibility for programs like TRICARE, which provides health insurance to military families. Individuals must keep their information updated in DEERS to ensure they receive the benefits they are entitled to, especially during life changes such as marriage or retirement.