Medicare Annual Enrollment Period: What You Need to Do Before It Ends

Every fall, Medicare runs a fixed window when beneficiaries can make changes to their coverage. If you miss it, you're largely locked into your current plan for another year. Here's what the Annual Enrollment Period (AEP) actually covers, who it applies to, and how to think through what — if anything — you should do before it closes.

What Is the Medicare Annual Enrollment Period?

The Medicare Annual Enrollment Period runs from October 15 through December 7 each year. Any changes you make during this window take effect on January 1 of the following year.

This is the one time most Medicare beneficiaries can freely switch, join, or drop certain types of coverage without needing a qualifying life event. Outside of this window, your options are generally much more limited.

It's worth distinguishing AEP from other enrollment periods:

What Can You Actually Change During AEP?

During the Annual Enrollment Period, most beneficiaries can:

• Switch from Original Medicare to a Medicare Advantage (Part C) plan
• Switch from Medicare Advantage back to Original Medicare
• Change from one Medicare Advantage plan to another
• Join, switch, or drop a Part D prescription drug plan

What AEP does not cover, for most people, is Medicare Supplement (Medigap) insurance. Medigap has its own enrollment rules — typically tied to when you first enroll in Medicare Part B — and insurers in most states can use medical underwriting if you try to switch outside that window. This is a meaningful distinction that catches many people off guard.

Why You Shouldn't Automatically Stick With Your Current Plan 📋

It's tempting to do nothing. But plans change every year — and doing nothing is still a choice.

Each year, Medicare Advantage and Part D plans can adjust:

• Premiums (monthly costs)
• Deductibles and copays
• Which drugs are covered (formulary)
• Which doctors and hospitals are in-network
• Star ratings (a quality measure that can shift year over year)

If your plan changes and you don't review it, you might face higher out-of-pocket costs, lose access to a preferred doctor, or find that a medication you rely on is no longer covered at the same tier.

Every Medicare plan is required to send an Annual Notice of Change (ANOC) to enrollees before October 15. This document outlines what's changing in your plan for the coming year. Reading it — even briefly — is one of the most useful things you can do before AEP closes.

Key Factors That Shape What You Should Review

There's no single right answer for everyone. What matters to one person may be irrelevant to another. The main factors that tend to drive coverage decisions during AEP include:

Your health status and expected care needs Someone who expects surgery, ongoing specialist visits, or significant prescription use in the coming year has different priorities than someone in generally good health. Higher expected utilization often makes cost-sharing structures more important to evaluate carefully.

Your current medications Part D formularies — the list of covered drugs — vary significantly between plans, as do the tier levels that determine your cost-sharing. If your drug regimen has changed, or if your current plan has shifted which tier your medications fall on, that alone can be a reason to compare alternatives.

Your preferred providers Medicare Advantage plans use networks. If your doctor has left your plan's network, or if you're considering switching to an MA plan from Original Medicare, checking whether your providers participate is critical.

Your financial situation Lower-premium plans often come with higher cost-sharing when you actually use care. Higher-premium plans may save money for people with frequent medical needs. The math looks different depending on how much care you actually use.

Where you live Plan availability varies significantly by county. Someone in a rural area may have far fewer Medicare Advantage options than someone in a metropolitan area.

How to Compare Plans Before the Deadline ⏰

The primary tool for comparison is Medicare Plan Finder, available at medicare.gov. You can enter your medications, preferred pharmacy, and doctors to see how different plans would cover your specific needs.

When comparing plans, look beyond the monthly premium. The total estimated annual cost — including premiums, deductibles, and estimated out-of-pocket costs based on your typical utilization — gives a more realistic picture than premium alone.

If you're comparing Part D plans specifically, inputting your exact medications with dosages is important because the same drug can be covered very differently across plans.

Don't Overlook These Easy Wins

A few things worth checking before December 7 that many people skip:

• Extra Help / Low Income Subsidy (LIS): If your income and assets are below certain thresholds, you may qualify for a program that helps pay Part D costs. Eligibility is worth checking if your situation has changed.
• Medicare Savings Programs: State-administered programs that can help with Part B premiums and other costs for qualifying individuals. These operate separately from AEP but are worth knowing about.
• Five-star plans: CMS assigns star ratings to Medicare Advantage and Part D plans. Plans with a 5-star rating can be joined at any time of year using a special enrollment period — so if a 5-star plan is available in your area, you're not strictly limited to the AEP window to join it.

What Happens If You Miss the Deadline?

If December 7 passes without any action, you remain enrolled in your current coverage as it stands for the coming year. For most people, changes won't be possible until the next AEP — unless a qualifying life event triggers a Special Enrollment Period. 🗓️

Common SEP triggers include moving to a new service area, losing other coverage, qualifying for Medicaid, or changes in a plan's contract status with Medicare. These are exceptions, not the norm, so treating the AEP deadline as a hard cutoff is the safer assumption.

What to Actually Do Right Now

Whether you end up making changes or not, the most valuable use of the AEP window is an active review — not passive assumption that nothing has changed.

• Pull out your Annual Notice of Change if you're currently enrolled in an MA or Part D plan
• List your current medications, providers, and anticipated care needs
• Use Medicare Plan Finder to compare your current plan against available alternatives
• If your situation is complex — multiple chronic conditions, significant drug costs, or confusion about how Medicare interacts with other coverage — a State Health Insurance Assistance Program (SHIP) counselor can provide free, unbiased help

What makes sense for you depends on your health, finances, location, and how your current plan has changed. The AEP window exists precisely so you can make that evaluation on your own terms, once a year, before it closes.