The short answer
The biggest Medigap mistakes revolve around timing. When you first enroll in Medicare Part B at 65 or older, you get a one-time open enrollment window during which insurers must sell you any Medigap policy at the best rate regardless of your health. Miss that window, and in most cases insurers can use medical underwriting to charge you more or deny coverage. So the costliest mistakes are missing your guaranteed-issue window, assuming you can always switch later, and not comparing insurers for the same standardized plan. Knowing the rules protects both your access and your price.
So the biggest Medigap mistakes are timing errors — missing your guaranteed-issue window and assuming you can freely switch later.
The mistakes to avoid
Common errors include missing your one-time Medigap open enrollment window, when acceptance is guaranteed; assuming you can switch from Medicare Advantage to Medigap anytime without underwriting, which is often not the case; buying the first policy offered without comparing insurers for the same plan letter; and choosing a plan on price alone without considering how premiums rise with age. Our guide to the Medigap 6-month open enrollment window explains the timing that matters most.
The recurring theme is protecting your one-time guaranteed-issue right and comparing insurers rather than acting on the first offer.
How to get it right
Enroll in Medigap during your open enrollment window if you want a supplement, since that is when acceptance is guaranteed. Compare premiums across insurers for your chosen plan letter, since benefits are identical, and consider how each insurer's rates change with age. If you are choosing between Medigap and Medicare Advantage, understand that switching later can require underwriting. A local licensed advisor can help you avoid these mistakes at no cost. Our Medicare Supplement page covers the basics.
The takeaway: avoid Medigap mistakes by using your guaranteed-issue window, comparing insurers for the same plan, and understanding that switching later can require underwriting.
Frequently Asked Questions
What is the biggest Medigap enrollment mistake?
Missing your one-time Medigap open enrollment window, when insurers must sell you any policy at the best rate regardless of health. After it, they can often use underwriting to charge more or deny coverage.
Can I switch from Medicare Advantage to Medigap anytime?
Often not without medical underwriting, which can raise your price or lead to denial. Assuming you can freely switch later is a common and costly Medigap mistake.
How do I avoid Medigap mistakes?
Enroll during your guaranteed-issue window, compare insurers for the same standardized plan letter, and understand that switching later can require underwriting. A local advisor can help.
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