Top Mistakes People Make When Enrolling in Medicare (and How to Avoid Them)

1. Waiting Too Long to Sign Up for Medicare

The issue:
You’re not automatically enrolled in Medicare at 65 unless you’re already receiving Social Security benefits at least four months before your birthday. If you delay enrollment, you risk permanent late penalties, especially for Medicare Part B, which adds 10% to your premium for every full year you wait.

Why it matters:
Premium subsidies from Affordable Care Act (ACA) marketplace plans end when you become eligible for Medicare Part A. Missing the enrollment window means you could face higher costs for the rest of your life.

How to avoid it:

• If you’re not automatically enrolled, sign up during your Initial Enrollment Period (IEP)—three months before, the month of, and three months after your 65th birthday.
• In Puerto Rico, you’ll automatically get Part A, but must apply separately for Part B.
• Missed it? Use the General Enrollment Period (Jan. 1–Mar. 31), or a Special Enrollment Period if you have qualifying job-based coverage.

2. Overlooking Your Special Enrollment Period

The issue:
When employer-sponsored coverage ends—yours or your spouse’s—you have just eight months to sign up for Part B without a penalty. Many assume retiree coverage or COBRA counts, but Medicare doesn’t treat these as “active job-based” insurance.

How to avoid it:

• Plan ahead. Sign up before your employment coverage ends, so there’s no gap.
• Remember: retiree plans and COBRA don’t extend your special enrollment rights.

3. Not Realizing Your Work Insurance Might Be Secondary

The issue:
If your employer has fewer than 20 employees, Medicare usually becomes your primary coverage at 65. Your job’s plan pays only after Medicare, meaning if you skip enrolling, you could be stuck with the bill.

How to avoid it:

• Ask your HR or benefits manager if your insurance will be primary or secondary after you turn 65.
• If it’s secondary, sign up for Medicare during your IEP to ensure claims get paid.

4. Misunderstanding Medicare’s Late Enrollment Penalties

The issue:

• Part B: 10% premium increase for every year you delay without qualifying coverage. Learn more about the Medicare Part B late enrollment penalty.
• Part D: 1% increase in your drug plan premium for each month you go without creditable prescription coverage.

How to avoid it:

• Maintain qualifying job-based coverage until you enroll.
• Keep proof of “creditable” prescription drug coverage to avoid Part D penalties.
• If you lose coverage, you have two months to get a Part D plan without penalty.

5. Skipping the Comparison Between Original Medicare and Medicare Advantage

The issue:
Many people stick with what they know or choose a plan for the wrong reasons. Later, switching can be difficult or costly. 

How to avoid it:

• Original Medicare: Federally run, includes Parts A & B, but no out-of-pocket cap. You can add a Medigap policy and Part D plan.
• Medicare Advantage (Part C): Private plans that bundle A, B, and usually D, often with extra benefits like routine dental or vision—but may have network limits.
• Review your doctor’s recommendations, travel habits, and health needs before making a decision.

6. Delaying Your Medicare Supplement (Medigap) Enrollment

The issue:
If you want a Medigap policy to cover Original Medicare’s deductibles and coinsurance, you get a six-month guaranteed-issue window after enrolling in Part B. Wait too long, and insurers can deny coverage or charge more if you have preexisting conditions.

How to avoid it:

• Compare Medigap plans and enroll during your open enrollment window.
• Contact your State Health Insurance Assistance Program (SHIP) for help if you’ve missed it.
  

7. Ignoring Medicare’s Coverage Gaps

The issue:
Medicare isn’t free. You’ll face premiums, deductibles, copayments, and coinsurance—and without supplemental insurance, those costs add up.

How to avoid it:

• Make sure providers accept Medicare “assignment” to avoid extra charges.
• Get Medigap or other supplemental coverage for Original Medicare.
• If you choose Medicare Advantage, know your plan’s annual out-of-pocket maximum.
• For Part D, review plan costs and coverage yearly.

8. Picking a Medicare Advantage Plan Without Checking Your Doctors

The issue:
Plans may restrict you to in-network providers or charge more for out-of-network care. Extra perks like dental or gym memberships can distract you from the real question: Are your doctors covered?

How to avoid it:

• Confirm your physicians and specialists are in-network.
• Review out-of-network costs and rules before enrolling

Learn more from our checklist on key questions before choosing a Medicare Advantage plan.

9. Overlooking Prescription Drug Coverage Details

The issue:
If your medications aren’t on a plan’s formulary, you could face high out-of-pocket costs—or no coverage at all.

How to avoid it:

• Each fall, review your plan’s drug list during Medicare Open Enrollment (Oct. 15–Dec. 7).
• Check for prior authorization requirements, quantity limits, and preferred pharmacy discounts.

10. Thinking You Can’t Afford Medicare

The issue:
Some skip Medicare because they assume the costs are too high, not realizing there are programs to help.

How to avoid it:

• Medicare Savings Programs: Can cover Part B premiums and other costs.
• Extra Help: Reduces prescription drug costs.
• State programs: Some states offer assistance or discount cards for eligible residents.

Contact your SHIP or visit Medicare.gov to see if you qualify.

Bottom Line

Medicare offers essential health coverage for millions, but missing deadlines, misunderstanding the rules, or overlooking your options can cost you dearly. By learning the common pitfalls now and taking proactive steps, you can protect your health and your wallet for years to come.

Easily compare Medicare plan options here, or consider speaking with a licensed Medicare advisor for guided assistance throughout the whole process.