GEP
The GEP — General Enrollment Period — is Medicare's catch-up window, January 1 to March 31 each year, for people who missed their Initial Enrollment Period and have no SEP. Coverage starts the month after you sign up, and the late penalty rides along.
The window nobody plans to use
The GEP exists for the missed-it cases: decline Part B at 65 without creditable coverage, change your mind in May, and January is the next door — with coverage the following month and the 10%-per-year penalty attached for life. Its sharpest edge on this site: a TFL or CHAMPVA beneficiary who dropped Part B has no coverage from the wraparound either until a GEP signup restores B — the decline-B trap measured in months of exposure. The whole architecture of the 8-month SEP exists so working people never meet this paragraph; the penalty calculator prices what meeting it costs.
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.