11 Things Retirees Must Do Before Enrolling or Renewing Medicare Coverage

Turning 65 can feel like a high-stakes test you didn’t study for. This is especially true with Medicare. With over half of all beneficiaries now in Medicare Advantage plans in 2025, the “right” choice is harder than ever.

Choosing the wrong plan or missing a deadline is a big deal. It can lead to gaps in your healthcare. You could face thousands of dollars in extra costs.

Worse, you might get lifelong monthly penalties that only get bigger over time.

We will walk you through every critical step. You’ll learn about your enrollment window, how to compare plans for free, and how to avoid the most common, costly mistakes.

1. Know Your Enrollment Period (It’s Not Just Once)

It is the most important step. Missing your deadline is the easiest way to get a lifelong penalty. You have several chances to enroll, but your first one is the most important.

This 7-month window around your 65th birthday is called your Initial Enrollment Period. If you (or your spouse) are still working past 65 with health coverage, you can use a Special Enrollment Period later.

For current beneficiaries, the Annual Enrollment Period is for switching plans.

• Your Initial Enrollment Period (IEP) is the 7-month window around your 65th birthday.
• A Special Enrollment Period (SEP) lets you enroll later without penalty if you have creditable coverage from work.
• The Annual Enrollment Period (AEP) from Oct. 15 to Dec. 7 is for switching or renewing existing plans.
• The General Enrollment Period (GEP) is a last-chance option that usually involves penalties.

2. Learn the “Alphabet Soup” Parts A, B, C, and D

Medicare is split into four main parts. It can seem confusing, but it’s simpler when you break it down. Think of them as building blocks for your health coverage.

Part A and Part B are “Original Medicare” from the government. Part C and Part D are private plans that offer different ways to get your coverage.

Understanding this “soup” is the first step to knowing what you are buying.

• Part A (Hospital) covers inpatient hospital stays. It’s usually premium-free.
• Part B (Medical) covers doctor visits and outpatient care. It has a monthly premium.
• Part C (Medicare Advantage) bundles A, B, and often D into one private plan.
• Part D (Prescription Drugs) provides your medication coverage.

Part	What It Is	What It Covers
Part A	Hospital Insurance	Inpatient stays, skilled nursing
Part B	Medical Insurance	Doctor visits, outpatient care
Part C	Medicare Advantage	All-in-one private plans (bundles A, B, D)
Part D	Prescription Drugs	Medications

3. Make Your First Big Decision Original Medicare vs. Medicare Advantage

After you have Parts A and B, you face a major choice. You must pick one of two main paths for your health coverage. The first path is Original Medicare, which is the traditional government-run program.

The second path is Medicare Advantage, which uses private insurance companies. There is no single “best” choice. It all depends on your health, budget, and if you want flexibility or bundled benefits.

• Original Medicare offers flexibility. You can see any doctor in the U.S. that accepts Medicare.
• Medicare Advantage offers an all-in-one plan. It often includes drug coverage, dental, and vision, but has a limited network of doctors.
• In 2025, over 34 million Americans are in Medicare Advantage plans.
• Your choice depends on if you prefer provider flexibility or lower-premium, bundled plans.

4. Don’t Forget Part D (Even If You Don’t Take Prescriptions)

Pay close attention to this step. Even if you take zero prescriptions right now, you need a plan for Part D (drug coverage).

If you go 63 days or more without Part D or other creditable drug coverage after your IEP, you will face a lifelong late enrollment penalty. This penalty is added to your Part D premium every month, forever.

It is often cheaper to sign up for a very low-cost Part D plan now than to pay a permanent penalty later.

• The Part D late penalty is permanent and is added to your premium for life.
• The penalty is 1% of the national base premium for every month you waited to enroll.
• For 2025, the base premium is $36.78. Waiting just 14 months could add over $5.15 extra to your bill every month.

5. Evaluate Your Need for a Medigap (Supplement) Plan

This step is only for people who choose Path 1 Original Medicare. Medigap plans, also called Supplements, are sold by private companies.

They help pay for the “gaps” that Original Medicare doesn’t cover, like your 20% coinsurance for Part B services.

A Medigap plan can save you from large, unpredictable medical bills. This is a crucial piece of the puzzle if you want stable costs.

• Your 6-month Medigap Open Enrollment Period starts the month you turn 65 and are enrolled in Part B.
• This is your one and only guaranteed-issue window.
• During this window, companies cannot deny you coverage or charge you more based on your health history.
• If you miss this window, you may not be able to buy a Medigap plan later.

6. Stop All HSA Contributions

It is a common and costly mistake for people working past 65. Once you are enrolled in any part of Medicare, even premium-free Part A, it is illegal to keep contributing money to a Health Savings Account (HSA).

If you keep contributing, you will face tax penalties from the IRS. You must stop all contributions, including any from your employer, before your Medicare coverage starts.

• Stop your HSA contributions 6 months before you plan to enroll in Medicare or file for Social Security.
• This is because Part A coverage can be backdated up to 6 months.
• This overlap can cause a 6% excise tax penalty from the IRS on the extra contributions.

7. Compile Your Complete Prescription Drug List

It is the single most important task for comparing Part D or Medicare Advantage plans. A plan that’s perfect for your spouse could be a terrible, expensive choice for you. Do not just guess.

You need to make a precise list to enter into the official plan finder tool. A $0 premium plan might look good, but it could cost you thousands more if your main drug isn’t covered well.

• Write down the exact Drug Name (e.g., Atorvastatin).
• Include the specific Dosage (e.g., 40mg) and Frequency (e.g., 1x per day).
• Note the Pharmacy you prefer to use.
• This list is essential for using the Medicare.gov Plan Finder tool correctly.

8. Check Your Doctor and Hospital Networks

If you picked Original Medicare, you can likely skip this step. You can see any doctor who accepts Medicare. But if you are considering a Medicare Advantage (Part C) plan, this is non-negotiable.

These plans use networks (HMO or PPO) to keep costs down. Your long-time doctor or preferred hospital might not be in the network. Going out of network could cost you thousands or not be covered at all.

• Do not just trust the plan’s online directory, which can be outdated.
• Call your doctor’s billing office directly.
• Ask them, “Do you accept the [Plan Name] Medicare Advantage plan for 2026?”
• Confirm this for all your specialists and your preferred hospital.

9. Know the 2025 Part D Change The $2,000 Cap

It is a major, positive change for all retirees starting in 2025. Thanks to the Inflation Reduction Act, there is now a $2,000 out-of-pocket cap on prescription drugs for anyone with a Medicare Part D plan.

It ends the old “catastrophic coverage” phase, where people with very high drug costs could still pay 5% of the cost with no limit. This new cap makes your annual drug costs much more predictable.

• Starting in 2025, your spending on covered drugs is capped at $2,000.
• After you hit the $2,000 cap, you will pay $0 for your drugs for the rest of the year.
• This hard cap does not include the monthly premium you pay for your plan.

10. For Renewals Read Your “Annual Notice of Change” (ANOC)

This step is the number one task for anyone who already has a Medicare Advantage or Part D plan. Your plan will mail you a document called the “Annual Notice of Change” (ANOC) by September 30.

Do not throw this away; it is not junk mail. This document details every single change to your plan for the upcoming year. The biggest mistake is “setting and forgetting” your plan.

• The ANOC will tell you if your premium, deductible, or copays are changing.
• It shows if your medications are still covered or moving to a more expensive tier.
• It lists any changes to the plan’s network of doctors and hospitals.
• Read this document to decide if you need to switch plans during the AEP.

11. Use the Official Free Tools (Medicare.gov and SHIP)

You do not have to do this alone, and you shouldn’t trust every TV ad or sales call. The two best resources are 100% free and unbiased.

The official Medicare website has a powerful Plan Finder tool. Beyond that, every state has a free counseling service.

Using these two resources is the single best way to make a confident, fact-based decision.

• The Medicare.gov Plan Finder lets you enter your drug list and compares the total annual cost for every plan in your area.
• SHIP (State Health Insurance Assistance Program) provides free, one-on-one counseling.
• SHIP counselors are trained volunteers who do not sell anything. They are not brokers.
• You can find your local SHIP office at shiphelp.org.