Top 10 Medicare Mistakes Members Make Yearly

Medicare can be a huge help—but it’s also full of rules, deadlines, and options that can trip people up. Every year, I see people make the same avoidable mistakes that lead to higher costs, unexpected bills, or coverage gaps.

Here are the top 10 Medicare mistakes people make each year, plus simple ways to avoid them.

1) Missing Enrollment Deadlines (and getting hit with penalties)

One of the biggest (and most expensive) mistakes is waiting too long to enroll in Medicare Part B or Part D when you’re supposed to.

Why it matters: Late enrollment can mean lifelong penalties and delays in coverage.

Avoid it: If you’re turning 65, plan ahead. If you’re still working, confirm how your employer coverage affects your Medicare timing.

2) Assuming Medicare Covers Everything

Many people believe Medicare works like “full coverage.” It doesn’t.

Common surprise costs:

• Deductibles and coinsurance (Original Medicare)

• Copays and out-of-pocket costs (Medicare Advantage)

• Prescriptions, dental, vision, hearing (often limited or not included depending on the route you choose)

Avoid it: Review what’s covered—and what isn’t—before you need it.

3) Choosing a Plan Based Only on the Monthly Premium

A $0 premium sounds great. But the premium is only one part of the story.

What to look at instead:

• Maximum out-of-pocket (MOOP)

• Specialist and hospital copays

• Deductibles

• Prescription costs

• Network rules

Avoid it: Compare total “worst-case” yearly cost—not just the monthly premium.

4) Not Checking Doctors and Hospitals for Network Coverage

This one happens constantly with Medicare Advantage plans.

Why it matters: A plan can look perfect on paper, but if your doctors or preferred hospital aren’t in-network, you may pay more—or have to switch providers.

Avoid it: Verify your primary doctor, specialists, and local hospitals before enrolling.

5) Not Reviewing Prescription Coverage Every Year

Your medications can change. So can the plan’s formulary (drug list), preferred pharmacies, and pricing tiers.

Avoid it: Each year, check:

• Are your meds covered?

• Are they covered with restrictions (prior authorization/step therapy)?

• Which pharmacy gives you the best pricing?

6) Ignoring the Annual Notice of Change (ANOC)

If you have a Medicare Advantage or Part D plan, your plan sends an Annual Notice of Change every year.

Why it matters: Your benefits, copays, provider network, or drug coverage can change for the next year—even if you do nothing.

Avoid it: Read the ANOC and compare options during Medicare’s annual enrollment season.

7) Mixing Up Medicare Supplement (Medigap) vs Medicare Advantage

These are not the same thing, but a lot of people think they are.

Quick difference:

• Medicare Advantage (Part C): A plan that replaces Original Medicare for your coverage, usually with networks and copays.

• Medigap: Works alongside Original Medicare to help cover “gaps” like deductibles/coinsurance (typically higher monthly premium, often less surprise billing).

Avoid it: Make sure you understand which path you’re choosing and why it fits your health and budget.

8) Waiting Too Long to Get a Medigap Plan (and then facing underwriting)

Many people don’t realize there’s a “best window” to get a Medigap plan.

Why it matters: Outside certain protected enrollment windows, you may have to answer health questions—and could be declined or charged more (rules can vary).

Avoid it: If you’re considering Medigap, talk through timing before your window closes.

9) Falling for TV Ads and “Too Good to Be True” Promises

The marketing can be loud, confusing, and sometimes misleading if you don’t know what to ask.

Avoid it:

• Don’t enroll without confirming your doctors, meds, and costs

• Ask for a clear breakdown of copays, MOOP, and network rules

• Work with someone who will actually compare options for your situation

10) Not Asking for Help (and guessing)

Medicare decisions affect your healthcare and finances. Guessing can get expensive fast.

Avoid it: A quick review can help you:

• Avoid penalties and gaps

• Confirm doctors and prescriptions

• Compare plan costs side-by-side

• Make changes confidently during enrollment periods

Bonus Tip: Do a “Medicare Checkup” Every Year

Even if you love your plan, it’s smart to review annually—because plan benefits and formularies can change, and your health needs can change too.