# Medicare Open Enrollment Guide for Seniors By Ronald Plocinski (@ronaldplocinski) ยท Published 2026-09-02 Canonical: https://voce.com/@ronaldplocinski/medicare-open-enrollment-guide-seniors-1g8ba1 --- Medicare's Annual Enrollment Period (AEP) is the fall window when people who already have Medicare can change the coverage they will carry into the new year. For New Hampshire seniors 65 and older, it runs each year from October 15 to December 7, and the work that matters now is reviewing your current plan before the deadline rather than assuming it still fits. The questions that decide a good Annual Enrollment are concrete. Will every drug you take still sit on your plan's formulary next year? Is your premium rising more than you would save by staying put? Does your Advantage plan still include the Dover doctors and New Hampshire hospitals you use? This guide lays out how to prepare so a change in your plan does not become a surprise you discover in January. At a glance: the Annual Enrollment window What you can change When (annual window) Who it is for When the change takes effect Pick a different Medicare Advantage plan October 15 to December 7 People already on Medicare January 1 of the next year Drop Advantage coverage and return to Original Medicare, with or without a Part D drug plan October 15 to December 7 People already on Medicare January 1 of the next year Join, drop, or change a standalone Part D prescription drug plan October 15 to December 7 People with Original Medicare January 1 of the next year Anyone already carrying Medicare can act inside this window. If you are turning 65 and not yet enrolled, this fall window is not your first move. Your personal Initial Enrollment Period, described later in this guide, handles a first time sign up, and understanding how the two periods differ keeps you from drifting into a late enrollment penalty. #### Key Takeaways - Medicare Annual Enrollment runs October 15 to December 7 every year, and it is for people already on Medicare who want to adjust coverage for the year ahead. - Your single most useful document is the Annual Notice of Change, the fall mailing that lists next year's premiums, deductibles, and drug tiers for your specific plan. - Before the deadline, confirm each of your prescriptions stays on your plan's formulary and compare whether a different Advantage or Part D plan saves you money. - If you are turning 65, first time sign up runs on your own Initial Enrollment Period clock, not the autumn window, so do not confuse the two. Medicare Annual Enrollment: October 15 to December 7 Medicare's Annual Enrollment Period (AEP) runs every year from October 15 to December 7, and it is for people who already have Medicare and want to adjust their coverage for the coming year, not for first time sign ups ([CMS](https://cms.gov/priorities/key-initiatives/medicare-open-enrollment-partner-resources)). In this window you can switch Medicare Advantage plans, change your standalone Part D prescription drug coverage, or move between Original Medicare and an Advantage plan. Staying put is the right call only when you have actually checked the details. CMS notes that if your current plan still meets your needs next year and is still being offered, you do not have to change anything during AEP. The risk is skipping the check itself, since plans regularly raise premiums and move drugs to higher tiers from one year to the next. ![Medicare annual open enrollment calendar and deadlines](https://www.usnews.com/object/image/0000019e-d5ef-d837-a7ff-ddefce400000/medicare-open-enrollment-timeline.png?update-time=1781705777274&size=responsiveFlow640) Do not rely on memory. Each plan mails an Annual Notice of Change (ANOC) every fall that lists next year's premiums, deductibles, and covered drugs for your specific policy. Reading it top to bottom is the reliable way to spot whether one of your drugs moved to a higher copay tier or your Advantage network shifted, then to compare before December 7. ## Your preparation checklist before the deadline The point of Annual Enrollment is to compare, not to guess. Before December 7, walk through these four checks so a real decision backs whether you stay or switch. 1. **Pull your Annual Notice of Change (ANOC)** for every plan you hold. That fall mailing is the official list of next year's premiums, deductibles, and covered drugs, and it is the starting point for every comparison you make. 2. **Check each prescription against the new formulary.** A drug that moves to a higher tier or drops off the covered list changes what you pay out of pocket, and most people only notice after a January pharmacy run. 3. **Compare at least one alternative.** If you are on an Advantage plan, price the standalone Part D plus Original Medicare combination; if you are on Original Medicare, check whether an Advantage plan covers your Dover doctors and the hospitals you actually use. 4. **Confirm your doctors and pharmacies stay in network.** Advantage plans change their provider lists each year, and a change you missed can mean a higher out of network bill after January 1. If the numbers point to a switch, make the change before December 7. Changes take effect January 1, so a decision made in January means you carry the current plan a full extra year. ## Turning 65: know your Initial Enrollment Period If you are turning 65 and have not yet enrolled, your own clock matters more than the autumn one. Your Medicare Initial Enrollment Period (IEP) runs for 7 months: the 3 months before the month you turn 65, the month you turn 65, and the 3 months after it ([Medicare.gov](https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start)). Your birthday month, not a government wide window, decides when you can first sign up for Part A and Part B. Enrolling early pays off literally, because coverage timing follows a simple rule. If you sign up during the 3 months before the month you turn 65, Part B coverage starts the month you turn 65. Sign up during the month you turn 65 or the 3 months after, and coverage begins the following month instead ([Medicare.gov](https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start)). If you miss the IEP entirely, you usually cannot sign up until the General Enrollment Period from January 1 to March 31, and you may owe a monthly late enrollment penalty for Part B that lasts as long as you carry the coverage, plus a wait until mid year for it to start ([Medicare.gov](https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start)). Because your IEP overlaps part of the autumn window, it can be tempting to assume the annual AEP will catch you if you wait. It will not. The two periods solve different problems, and waiting for AEP to handle a first time sign up at 65 is exactly how late enrollment penalties accrue.