Updated August 3, 2026. Quick answer: the annual window is not a reminder to shop — it is a reminder that your existing plan may have changed. Formularies, networks, tiers and costs are reset every January by the plan, not by you. Doing nothing is a decision to accept whatever it changed to.
Read the one document that matters
Your plan sends an annual notice of change each autumn. It is the only document that tells you what is different about your plan next year, and it is the one most reliably thrown away. Everything below is a way of reading it properly.
That letter has a name and a legal deadline attached to it: the Annual Notice of Change must reach you at least 15 days before the Annual Election Period opens, which is precisely the window this checklist is designed to use. It sits alongside the other letters Medicare sends in the notices index, sorted by how fast each one has to be answered.
The checklist
- Are all your drugs still on the formulary? A drug dropped from the formulary does not count toward the out-of-pocket cap and is not capped by it.
- Did any drug change tier? Same coverage, different cost.
- New restrictions? Prior authorisation, step therapy or quantity limits added to something you take.
- Is your pharmacy still preferred?
- Is every doctor you see still in network for next year? Check by name, in the plan’s directory for the coming year.
- Is your hospital still in network?
- What changed in the premium, deductible and out-of-pocket maximum?
- Did your income two years ago cross an IRMAA threshold? That surcharge arrives regardless of which plan you hold — why 2026 looks at 2024.
The thing the annual window does not let you do
This is the limit worth understanding, because it is where the annual window and the coverage decision come apart.
You can move into Medicare Advantage in these windows freely. You can return to Original Medicare in them too. What the annual window does not give you is the right to buy a Medigap policy — outside a guaranteed-issue right, that remains medically underwritten in most states.
So the annual window is a real opportunity for drug coverage and for Advantage plans, and it is not a reset button on the choice that has the one-way door in it. Why that asymmetry drives everything.
If nothing changed and you are happy
Then do nothing, deliberately, having checked. That is a different act from doing nothing because the envelope went unopened, and it is the only version that is actually a decision.
General information drawn from Medicare, CMS and state insurance-department publications, not insurance advice. Medicare rules, plan availability and dollar figures change every year, and state rules differ. Every figure here is year-labelled and every source is named so you can check it against your own situation. We do not sell insurance and receive nothing if you buy a plan.
Two things to settle before you start. Which window you are actually in — October versus the January Advantage window — and the mistakes that cost the most: Medicare open-enrollment mistakes.
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For a group session: the Medicare module uses this checklist as its close, after the enrolment window and the penalty.
The 2026 figures
Before you compare plans, the numbers you are comparing against: Medicare open enrollment statistics carries the household figures for 2026 with their year labels — the $202.90 Part B premium, the $283 Part B deductible, and the $1,736 Part A deductible that applies per benefit period rather than per year — plus paste-ready lines for anyone quoting them.