Medicare Open Enrollment Checklist: What to Do Before October 15

Why bother reviewing if your plan is fine?

Because “fine” is a moving target. Every year, Medicare Advantage and Part D drug plans are allowed to change their premiums, deductibles, drug lists, pharmacy networks, and doctor networks — and most of them do. The plan that covered your medication at a $10 copay last January can move it to a higher tier, drop it entirely, or add a prior-authorization hurdle for next year. If you do nothing, your plan renews automatically at next year's terms, not this year's. Open enrollment is the once-a-year chance to catch that before you're locked in for twelve months.

This is also the only stretch when nearly everyone on Medicare can make changes at the same time. The fall Annual Enrollment Period runs October 15 through December 7, and anything you change takes effect January 1. Miss it, and for most people the next chance is a full year away.

The five-minute-each checklist to finish before October 15

1. Read your Annual Notice of Change (ANOC)

If you're in a Medicare Advantage or Part D plan, your insurer mails you an Annual Notice of Change and an Evidence of Coverage each fall — plans begin sending them around October 1, so it should land in late September or early October. Don't file it unread. It has one job: to spell out exactly what's different about your plan next year. Flip to the summary-of-changes table and look for four things — a higher premium or deductible, your drugs moving to a costlier tier or falling off the list entirely, your doctor or pharmacy leaving the network, and any new prior-authorization rules. If nothing you rely on changed, you may be done. If something did, you now know exactly what to shop against.

2. Write down every prescription — with the dose

The single biggest driver of what a drug plan will cost you is whether it covers your medications well. Make a simple list: each drug's name, the dose, and how often you take it. Include the ones you take occasionally. When you compare plans on Medicare's Plan Finder, you can enter this list and see your real projected yearly cost under each plan — not the advertised premium, the actual total. Guessing here is how people end up overpaying by hundreds of dollars a year.

3. List your doctors and your pharmacy

Write down the doctors and specialists you want to keep seeing, and the pharmacy you actually use. Medicare Advantage plans have networks, and “in-network” status changes year to year — a plan that's cheap on paper is expensive if your cardiologist isn't in it. Part D plans also have preferred pharmacies where your copays are lower; the same plan can cost you more at the drugstore across the street than at the one a mile away. Knowing your pharmacy up front lets you compare apples to apples.

4. Add up what this year actually cost you

Pull together roughly what you paid in the past year: your monthly premiums, your deductible, and the copays or coinsurance you paid at the pharmacy and the doctor. This is your baseline. Without it, a lower premium looks like a win even when higher copays would wipe out the savings. For 2026, a couple of reference numbers help: the standard Part B premium is $202.90 a month with a $283 annual deductible, and no Part D plan can charge a deductible above $615. Your out-of-pocket spending on covered Part D drugs is also capped at $2,100 in 2026 — once you hit it, covered drugs cost you nothing for the rest of the year.

5. Note any changes in your life

Did you move, or spend part of the year in another state? Start a new medication? Get a diagnosis that means more specialist visits ahead? Retire and lose employer drug coverage? Each of these can change which plan fits — a snowbird needs nationwide access a local HMO won't give; someone facing a costly new drug should weigh a plan with a lower deductible even at a higher premium. Jot these down so they're part of the comparison, not an afterthought.

What actually changes from year to year

When you read your ANOC and compare plans, these are the moving parts worth the most attention:

• The drug list (formulary). Which medications are covered, and on which cost tier. This changes the most and hurts the most when it slips past you.
• The pharmacy and provider networks. Preferred pharmacies and in-network doctors shift every year.
• Premiums and deductibles. Both can rise; a plan can also lower its premium while raising what you pay when you actually use it.
• Extra benefits (Medicare Advantage). Dental, vision, hearing, and over-the-counter allowances get added and trimmed — don't assume last year's perks carry over.
• Prior authorization and referral rules. New hoops can appear for drugs or services you already use.

Once you've gathered it, comparing is the easy part

With your five items in hand, the Medicare Plan Finder at Medicare.gov does the heavy lifting: enter your drug list and pharmacy and it ranks plans by your total estimated yearly cost. If you're weighing bigger structural questions — whether to stay with Original Medicare and a supplement or move to an all-in-one plan — our guide on Medicare Advantage vs. Medigap walks through the trade-off, and how to compare Part D drug plans shows you what to look at beyond the premium. For the exact dates and what you're allowed to change in each window, see Medicare open enrollment: dates and what you can change.

A calm timeline

• Late September – early October: Your ANOC arrives. Read the summary of changes. Do your five-item prep.
• October 15: Open enrollment opens. Compare plans on Medicare.gov with your drug list loaded.
• By December 7: Make any change. Your plan must receive the request by this date.
• January 1: Your new coverage begins. Confirm your first prescription fills correctly.