Once a year, the door opens for nearly everyone on Medicare to rethink their coverage — and then it quietly closes again. That window is the Annual Enrollment Period, and a few minutes spent there can save you real money and headaches in the year ahead.
When the AEP happens
The Annual Enrollment Period (AEP) — sometimes called fall open enrollment — runs from October 15 through December 7 every year. Whatever changes you make during that window take effect on January 1 of the following year.
That timing is the same for everyone, so it’s easy to plan around. If you’d like to see how the AEP fits alongside your other Medicare dates, the Timeline Calculator lays them out for you, and the Enrollment Countdown shows exactly how many days are left before December 7 so the deadline doesn’t sneak up on you.
What you can do during the AEP
The AEP is your chance to adjust the parts of Medicare that come from private plans. During the window, you can:
- Join a Medicare Advantage plan or a standalone Part D drug plan
- Switch from one Medicare Advantage plan to another, or from one Part D plan to another
- Drop a Medicare Advantage plan and go back to Original Medicare
- Move between Original Medicare (with a Part D plan) and a Medicare Advantage plan
In other words, this is the time to rearrange your drug coverage and your Medicare Advantage choices however you like. You can make as many changes as you want during the window — the last one you submit by December 7 is the one that sticks.
One thing the AEP is not built for: buying or switching a Medigap (Medicare Supplement) policy. Medigap follows its own rules and isn’t tied to this window, so if that’s on your mind, it’s worth a separate conversation.
Why an annual review matters
Here’s the part people skip. If you do nothing, most plans simply renew for the next year — which feels easy, but it can quietly cost you. Plans are allowed to change every single year, and they often do:
- Formularies (drug lists) change. A medication that was covered this year might move to a higher cost tier, or off the list entirely.
- Networks change. Your doctor, pharmacy, or preferred hospital may leave the plan’s network.
- Costs change. Premiums, deductibles, and copays can all shift from one year to the next.
That’s why a quick yearly check-up pays off. Each fall, plans send out an Annual Notice of Change describing what’s different for the coming year — it’s worth reading that letter rather than tossing it. A good annual review usually comes down to three questions: Are my prescriptions still covered at a fair price? Are my doctors still in network? Is there a plan that fits me better now?
It’s also a good year to review your drug coverage in particular. In 2026, Part D has a $2,000 out-of-pocket cap on covered drugs, and the first round of Medicare drug price negotiations takes effect January 1, 2026, lowering the negotiated price on a list of common medications. What you actually pay still depends on your specific plan, so comparing options during the AEP is the way to make sure you’re getting the benefit.
Don’t confuse it with the spring window
There’s a second window that often gets mixed up with the AEP: the Medicare Advantage Open Enrollment Period, which runs January 1 through March 31. The two are not the same.
| Annual Enrollment Period | Medicare Advantage Open Enrollment | |
|---|---|---|
| Dates | Oct 15 – Dec 7 | Jan 1 – Mar 31 |
| Who it’s for | Nearly everyone on Medicare | Only people already in a Medicare Advantage plan |
| What you can do | Join, switch, or drop MA and Part D plans | Make one switch: to another MA plan, or back to Original Medicare + Part D |
So the spring window is a narrower, second-chance period — useful if you signed up for a Medicare Advantage plan in the fall and realized by February it wasn’t the right fit. But the AEP is the main event, and it’s the broadest opportunity you’ll get all year.
A simple plan for the fall
You don’t have to overhaul anything during the AEP. For most people, a smart approach looks like this: read your Annual Notice of Change when it arrives, list your current prescriptions and doctors, and check whether your plan still covers them well for the coming year. If it does, you can sit tight. If it doesn’t, you’ve got from October 15 to December 7 to make a better choice.
If you’d rather not sort through plan changes on your own — or you just want a second set of eyes before December 7 — that’s exactly what I do. Feel free to reach out for a no-pressure review, and we’ll make sure your coverage still fits before the new year begins.