1. Assuming You Can Switch Supplement Plans Every Year

This is one of the biggest misconceptions around Medicare.

When you first enroll in Medicare, you get a guaranteed right to choose any Medicare Supplement (Medigap) plan — no matter your health history. But that guarantee doesn’t last forever.

In most states, you’re not guaranteed to switch Supplement plans later unless you meet special conditions or live in a state with special rules (like New York or Connecticut).

Yes, you can switch Medicare Advantage or Part D plans during Open Enrollment every fall — but that flexibility does not apply to Supplement plans. That’s why it’s so important to get your coverage right when you first join.

2. Believing the $2,000 Prescription Cap Covers All Drugs

Starting in 2026, there’s a $2,100 cap on prescription drug costs — which sounds great, right?

But here’s the fine print: that cap only applies to drugs listed on your plan’s formulary (the list of medications that your plan covers). If your medication isn’t on that list, the cap won’t help you.

So before assuming you’re protected, make sure your medications are actually covered by the plan — otherwise, you could face unexpected costs.

3. Choosing a Plan Based Only on Premiums

It’s easy to focus on the monthly premium. After all, that’s the number you see most often.

But Medicare plans come with many other costs — including deductibles, co-pays, and maximum out-of-pocket limits. Some plans with lower premiums can actually cost more overall once you start using them.

Also, regardless of which plan you choose, you’ll still pay your Medicare Part B premium — unless you qualify for extra help. Some people mistakenly believe that going with a Medicare Advantage plan means no Part B cost. That’s not true — it’s always in addition.

So be sure to compare the full picture, not just the monthly price tag.

4. Overlooking Doctor Networks

Another common mistake? Not checking whether your doctor accepts your new plan.

If you choose Original Medicare, you’ll likely have access to about 95% of doctors nationwide. But if you go with a Medicare Advantage plan, the network is more limited — and your doctor may only accept specific Advantage plans, if any.

That’s why we always recommend double-checking with your providers before choosing a plan — especially if staying with your current doctor is important to you.

Make a Confident, Long-Term Medicare Decision

Medicare works best when you go into it with a plan — not just a plan for this year, but a plan that supports your health and finances for the long haul.