Every October, I get a call that sounds something like this: “Dana, I just got a letter saying my drug plan is changing next year and my insulin is going to cost twice as much. Can I do anything about it?” The answer is almost always yes, but only if we act before December 7th. That window, October 15 through December 7, is Medicare’s Open Enrollment Period, and it’s genuinely one of the most powerful tools you have as a Medicare beneficiary. Miss it, and you’re stuck with a plan that doesn’t serve you for a full year. Catch it at the right time, and you might save hundreds, sometimes thousands, of dollars.

What the Medicare Open Enrollment Period Actually Is

Let’s clear up some confusion right away, because the term “open enrollment” gets thrown around a lot and it means different things in different contexts.

The Medicare Open Enrollment Period, also called the Annual Enrollment Period or AEP, runs every year from October 15 through December 7. Any changes you make during this window take effect January 1 of the following year. This is your annual opportunity to review your Medicare coverage and make changes without answering health questions or proving special circumstances.

Here’s what most people don’t realize: you don’t have to do anything if your current coverage is working well. Open enrollment isn’t mandatory. But doing nothing is a decision too, and it’s one I’ve seen people regret when their plan quietly changes its benefits, drug formulary (the list of covered medications), or provider network for the new year.

During this period, you can:

  • Switch from Original Medicare (Parts A and B) to a Medicare Advantage plan (Part C)
  • Switch from a Medicare Advantage plan back to Original Medicare
  • Switch from one Medicare Advantage plan to a different one
  • Join a Medicare Part D prescription drug plan if you don’t have one
  • Switch from one Part D plan to another
  • Drop a Part D plan entirely (though this is rarely a good idea)

What you cannot do during AEP: change your Medicare Supplement Insurance (also called Medigap) policy in most states without medical underwriting. Medigap operates under separate rules.

Why You Should Review Your Plan Every Single Year

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I know. Reviewing your Medicare plan every year sounds like unnecessary work for something that might not change. Your plan changed. They almost always do.

Every fall, Medicare Advantage and Part D plans send out something called the Annual Notice of Change, sometimes called the ANOC. It arrives by September 30, so you should have it before open enrollment begins. Read it. Actually read it, not just set it on the counter with the intention of getting to it later.

Plans adjust their premiums, deductibles, copays, and covered drug lists year over year. A medication that cost you $10 per month this year might move to a higher tier next year, bumping your cost to $50 or more. A specialist you’ve been seeing might drop out of your plan’s network. These aren’t small details. They’re the things that determine whether you can afford your care.

What most people don’t realize is how dramatically plan options can shift even within the same zip code. AARP’s Medicare resource center notes that the number of available plans varies widely by location, and the plan that ranked best for you three years ago might not even be competitive today. New plans enter markets, existing plans sweeten their benefits to attract members, and the landscape genuinely reshapes itself every year.

How to Actually Compare Your Options (Step by Step)

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This is where people get overwhelmed, and I completely understand why. There are a lot of moving parts. But if you break it into steps, it’s manageable.

Step 1: Gather your information before you start.

You’ll need your Medicare card (or your Medicare number), a list of your current prescriptions with dosages, the names of your doctors and any specialists you see regularly, and your current plan information. Having all of this in front of you before you log on saves a lot of back-and-forth.

Step 2: Go to Medicare.gov and use the Plan Finder tool.

The Medicare Plan Finder at medicare.gov is genuinely good and it’s free. Enter your zip code and your drugs, and it will show you estimated annual costs across available plans. Don’t just look at the monthly premium. Look at the total estimated drug costs, the deductible, and the copay structure.

Step 3: Check your doctors are in-network.

If you’re considering a Medicare Advantage plan, call your primary care doctor and any specialists you see. Ask them directly: “Are you in-network for [plan name] for next year?” Don’t rely solely on the plan’s online directory. Those aren’t always updated in real time.

Step 4: Think about your expected health needs for the coming year.

Have a surgery planned? Starting a new medication? These things matter. A plan with a lower premium but higher hospital cost-sharing might cost you significantly more if you’re expecting inpatient care.

Step 5: Compare plans side by side.

What to CompareWhy It Matters
Monthly premiumYour guaranteed cost regardless of usage
Annual deductibleWhat you pay before coverage kicks in
Drug formulary tiersDetermines your out-of-pocket cost per prescription
In-network providersKeeps your care covered at the lower rate
Maximum out-of-pocket limitYour financial safety net for a bad health year
Extra benefits (dental, vision)Medicare Advantage often includes these; Original Medicare does not

Step 6: Enroll or confirm your choice before December 7.

If you want to switch plans, enroll in the new plan directly. In most cases, your new plan will automatically disenroll you from the old one. If you want to stay in your current plan, you don’t need to do anything.

Getting Help If You’re Stuck

You don’t have to figure this out alone, and I’d encourage you not to try.

The State Health Insurance Assistance Program, known as SHIP, offers free, unbiased Medicare counseling through a network of trained volunteers across every state. These aren’t salespeople. They have no plans to sell you and no commissions to earn. Find your local SHIP counselor at shiphelp.org. I’ve referred hundreds of clients there over the years and I’ve never heard a complaint.

If you’re comfortable online, the Medicare Plan Finder is a solid starting point. If you prefer talking to someone, calling 1-800-MEDICARE (1-800-633-4227) connects you to a representative who can walk you through your options. And if you want a deeper dive into supplement plans or want to understand your choices in writing, resources like a Medicare supplement insurance guide can be a helpful reference to have on hand. (Full disclosure: this site may earn a small commission on purchases, at no extra cost to you.)

One thing I’ll say plainly: be cautious about unsolicited calls or mailers that seem urgent or alarmist during open enrollment season. It’s prime time for aggressive insurance marketing. A legitimate counselor will never pressure you to decide on the spot.

Common Mistakes I See Every Year

I’ve been doing this long enough to recognize the patterns. Here are the ones that cost people the most.

Ignoring the ANOC letter. If your plan is changing your drug coverage and you don’t realize it until February, it’s too late to switch. Read that letter.

Choosing based on premium alone. A $0 premium plan might have a $500 hospital copay and a very narrow drug formulary. Total cost of ownership is what matters, not the monthly sticker price.

Assuming your doctors are still in-network. Provider networks change. Always verify, especially if you’ve recently started seeing a new specialist.

Confusing AEP with the Medicare Advantage Open Enrollment Period. There’s a separate window, January 1 through March 31, called the Medicare Advantage Open Enrollment Period (MA OEP). During that time, if you’re already enrolled in a Medicare Advantage plan, you can switch to a different Advantage plan or go back to Original Medicare (with the option to add a Part D plan). It’s a limited do-over, but it only applies to people already in Medicare Advantage, and you can only make one change.

Waiting until the last minute. Processing takes time. If you’re enrolling online, the system is usually seamless. But if you’re doing it by phone or mail, give yourself buffer before December 7.

Open enrollment doesn’t have to feel like a chore you dread every fall. Think of it as your annual check-in on one of the most important financial decisions in your life. Spend a few hours comparing your options, lean on free resources like SHIP counselors when you need support, and make a deliberate choice rather than letting inertia decide for you. Your future self, especially the one who might need that specialist or that prescription next March, will be grateful you did.

Sources

Disclosure: As an Amazon Associate, we earn a small commission from qualifying purchases at no extra cost to you. We only recommend products that genuinely support the topics covered in this article.

  • Medicare For Dummies (~$22), The definitive consumer guide to Medicare, enrollment windows, Part A/B/C/D, and supplement plans.
  • Get What’s Yours for Medicare (~$17), Maximize your Medicare benefits and minimize out-of-pocket costs. Covers Part D drug coverage gaps and Medigap in depth.

Disclosure: As an Amazon Associate, we earn a small commission from qualifying purchases at no extra cost to you. We only recommend products that genuinely support the topics covered in this article.

  • Medicare For Dummies (~$22), The definitive consumer guide to Medicare, enrollment windows, Part A/B/C/D, and supplement plans.
  • Get What’s Yours for Medicare (~$17), Maximize your Medicare benefits and minimize out-of-pocket costs. Covers Part D drug coverage gaps and Medigap in depth.