Medicare Mistakes to Avoid

Medicare decisions carry real consequences — some reversible, some not. Here are the mistakes we see most often, and how to steer clear of them.

1. Missing Your Initial Enrollment Period

Your Initial Enrollment Period (IEP) is a 7-month window around your 65th birthday. Miss it without qualifying for a Special Enrollment Period (generally tied to active employer coverage), and you could face:

  • A late enrollment penalty for Part B — an amount added to your premium, for as long as you have Part B, based roughly on how long you went without coverage
  • A gap in coverage until the next enrollment period opens
  • A late enrollment penalty for Part D if you went 63+ days without creditable prescription drug coverage

These penalties aren’t one-time fees. They can follow you for the rest of the time you’re on Medicare.

2. Assuming You’re Automatically Covered While Still Working

Whether you need to sign up for Medicare at 65 while still working depends on your employer’s size — generally, whether the employer has 20 or more employees changes whether Medicare or your group plan is “primary.” People who assume they’re automatically fine sometimes find out too late that they needed to enroll, and end up with gaps or penalties.

3. Picking a Plan Based on Premium Alone

The plan with the lowest monthly premium isn’t always the cheapest option once you factor in your actual medications and doctors. A drug that’s a low tier on one plan’s formulary might be a high tier — or not covered at all — on another. Always check:

  • Whether your specific medications are covered, and at what tier
  • Whether your current doctors and hospitals are in-network
  • What the plan’s total out-of-pocket maximum is, not just the premium

4. Missing Your Medigap Open Enrollment Window

If you plan to pair Original Medicare with a Medigap (Medicare Supplement) policy, there’s a specific 6-month window — starting when you’re 65+ and enrolled in Part B — where insurers must accept you regardless of health conditions. Miss that window, and in most states, insurers can use medical underwriting to deny coverage or charge more based on your health history. This is one of the most permanent mistakes on this list.

5. Not Reviewing Coverage Every Year

Medicare Advantage and Part D plans can change their costs, covered drugs, and networks from year to year — even if you don’t change anything on your end. A plan that was perfect for you last year might not be this year. The Annual Enrollment Period (October 15 – December 7) exists specifically so you can review and adjust. Skipping this review is one of the quieter, more common mistakes — nothing dramatic happens, you just quietly overpay or lose coverage for something you need.

6. Assuming Original Medicare Covers Everything

Original Medicare doesn’t have an annual out-of-pocket maximum, and it doesn’t cover routine dental, vision, or hearing care, or long-term custodial care. Some people are surprised by this well after they’ve already enrolled. Understanding what’s not covered is just as important as understanding what is.

7. Working with Someone Who Only Offers One Company’s Plans

Some agents can only sell plans from a single insurance company. That’s not necessarily dishonest, but it does mean you may never see the plan that would’ve actually fit you best. Working with someone who can compare multiple carriers side by side gives you a fuller picture before you commit.

8. Making a Big Decision Alone, Under Time Pressure

Enrollment deadlines are real, but the best decisions come from understanding your options ahead of time — not scrambling in the final days of a window. Start the conversation early, even if you’re not ready to decide yet.

This article is educational and general in nature. We do not offer every plan available in your area; please contact Medicare.gov or 1-800-MEDICARE for information on all of your options.

Want a second set of eyes on your current coverage, or help avoiding these mistakes from the start? Schedule a free, no-pressure consultation.