Medicare has three main doors, and each opens on its own schedule. Knowing which one applies to you is most of the battle.
1. Your Initial Enrollment Period
Your first window is seven months long: the three months before the month you turn 65, your birthday month, and the three months after. Enroll in Part B late without qualifying coverage and your premium rises 10% for every 12 months you waited — permanently. The Part D late penalty works the same way and also lasts for life.
2. The Annual Election Period
Every year from October 15 through December 7, you can switch between Medicare Advantage and Original Medicare, change Advantage plans, or change drug plans. Changes take effect January 1. This is the window where an annual review earns its keep: plans change their networks, formularies and costs every single year, even when your letter says "no action needed."
3. Special Enrollment Periods
Certain life events open a window outside the calendar: leaving employer coverage after 65, moving out of your plan's service area, or losing other creditable coverage. The rules and deadlines differ by event — the employer-coverage window, for example, runs eight months for Part B but only 63 days for drug coverage.
What to do with this
Put two dates on your calendar: the month you turn 64 and a half, and October 15 of every year after. A licensed advisor can map your exact windows in one conversation — at no cost — and the review each fall makes sure last year's right answer is still this year's.
