DEERS
DEERS — the Defense Enrollment Eligibility Reporting System — is the database that proves military-benefit eligibility. For TRICARE for Life it IS the enrollment: keep DEERS current, hold Medicare Parts A and B, and TFL exists; there's no separate application or card.
The database that does the enrolling
TFL has no sign-up because DEERS plus Medicare is the sign-up: Medicare reports your Part A and B effective dates into the record, and providers verify everything from your Medicare card plus uniformed services ID. Stale records — an old address, an unrecorded life event, a mismatch with Social Security's file — are the leading cause of TFL claim hiccups, which makes the maintenance channels worth saving: milConnect online, any ID card office, or 800-538-9552.
Life events are the trigger points: marriage, divorce, a death, a dependent aging toward their own Medicare. Update DEERS first and the benefits follow; update it last and the claims bounce in between.
You earned these benefits. Make them work together.
Whether you keep exactly what you have or add Medicare coverage alongside it, the right answer depends on your health, budget, and how you like to get care.
No cost, no obligation. You can also get help from Medicare.gov, 1-800-MEDICARE (TTY 1-877-486-2048), or your local SHIP office.