Medicare Open Enrollment Prep: Start Before Oct. 15

Most years I treated Medicare open enrollment like a deadline I would deal with when it arrived. That was a mistake. The homework is what takes time, and this year I can start it before the window even opens.

Medicare Open Enrollment runs October 15 through December 7, 2026, and any changes take effect January 1, 2027, according to Medicare. The useful surprise: 2027 plan prices went live on the Medicare Plan Finder on October 1, two weeks before enrollment opens. That gives me through October 14 to compare calmly, instead of rushing when everyone else is panicking.

This article is educational, not financial advice. It is the checklist I am using myself, and the one I would hand to anyone helping a parent through the same process.

Figure: Key dates for the 2026 Medicare open enrollment window. Milestones are shown evenly spaced, not to calendar scale. Sources: Medicare (medicare.gov) for enrollment dates and the Plan Finder; AARP estimate reported October 2026 for COLA timing.

Why the Two Weeks Before Oct. 15 Matter

During open enrollment, Medicare says I can switch from Original Medicare to Medicare Advantage, switch back, change Medicare Advantage plans, and join, drop, or switch a Part D drug plan. None of that rewards a snap decision.

So I split the job in two. Before October 15, I only gather and compare — no switching, no forms, no sales calls. Once enrollment opens, I already know which plan, if any, I want, and the change takes minutes.

First, I pull out the Annual Notice of Change letter from my current plan. Plans can change costs and coverage each year, and that letter is where they have to tell me what is changing for 2027.

The Three Checks I Do Every Year

First, I check my drugs. I take my prescription list into the Medicare Plan Finder at medicare.gov/plan-compare and confirm each drug is still on the plan's formulary for 2027, and which tier it sits on. A drug that moves up a tier can cost more even if the premium does not change.

Second, I check my doctors and hospital. Networks change too, so I confirm the doctors I actually see, and the hospital I would actually use, are still in network for 2027. A cheaper plan that loses my doctor is not cheaper in any way that matters.

Third — the one I got wrong for years — I compare total cost, not just the premium. I add up the deductible and look hard at the out-of-pocket maximum. A low premium paired with a high deductible and a high out-of-pocket ceiling can be the more expensive plan in a year when I actually need care.

If I get stuck, I do not call a number from a TV ad. I use the free help that already exists: the Plan Finder, and State Health Insurance Assistance Program (SHIP) counselors, who state programs such as Alabama SHIP describe as free and not affiliated with insurers.

If You Are Doing This for a Parent

A lot of readers will be doing this at a kitchen table for a parent, and that changes the job slightly, not the checklist.

I start by asking for three things: the current plan card, the Annual Notice of Change letter, and a written list of prescriptions with dosages. With those, the Plan Finder comparison takes under an hour. Without them, it takes all weekend.

I also keep my parent in the decision. I can run the numbers and narrow it to two options, but it is their doctor, their pharmacy, and their money. My job is to make the trade-offs clear, not to pick for them.

The COLA Number to Watch on Oct. 14

One more date belongs on the calendar. AARP estimates the 2027 Social Security cost-of-living adjustment at about 3.6 percent, roughly $75 a month more for the average retired worker. To be clear: that is an AARP estimate, not the official number. The official COLA is expected October 14, the day before enrollment opens.

The arithmetic is simple: $75 a month times 12 months is about $900 a year. That does not decide which plan I pick, but it belongs in the same budget conversation. If my plan costs rise in 2027, knowing whether roughly $900 in estimated extra income is coming helps me judge the increase honestly instead of reacting to the premium headline.

My plan for the next two weeks is unglamorous: read the change letter, run the three checks, write down the plans worth switching to. Then October 15 is a formality.

FAQ

When does Medicare open enrollment run in 2026?

October 15 through December 7, 2026, according to Medicare. Changes take effect January 1, 2027.

Can I compare 2027 plans before enrollment opens?

Yes. 2027 prices went live on the Medicare Plan Finder on October 1, 2026. Compare now at medicare.gov/plan-compare and decide before October 15.

What can I change during open enrollment?

According to Medicare, you can switch between Original Medicare and Medicare Advantage, change Advantage plans, and join, drop, or switch a Part D drug plan.

What should I check before I switch plans?

That your drugs are still on the 2027 formulary and their tier, that your doctors and hospital are still in network, and the total cost — deductible plus out-of-pocket maximum, not just the premium. Start with your Annual Notice of Change letter.

Where can I get free help, and how big is the 2027 COLA?

Use the Plan Finder and your State Health Insurance Assistance Program (SHIP); counselors are free and, as Alabama SHIP notes, not affiliated with insurers. On COLA, AARP estimates about 3.6 percent — roughly $75 a month, or about $900 a year — but that is an estimate only; the official figure is expected October 14, 2026.