If you're on traditional Medicare, you should read this...

A company called eHealth asked a thousand people if they understood their Medicare coverage. Almost 9 out of 10 said yes, they had it handled. Then the company actually quizzed them, and only about 1 in 10 could name the basic parts of the program.

I'm not telling you that to make anybody feel dumb. Medicare is confusing, and nobody hands you a manual when you turn 65. But five of those gaps show up later as a bill, and I want you to know about them while you can still do something.

Medicare doesn't stop charging you at any point in the year

If you've had insurance through a job, you're probably used to the idea that your costs eventually stop. You pay so much for the year, and after that the plan covers everything. Original Medicare doesn't have that. There is no ceiling. If you get seriously sick, the bills just keep coming, and nothing in the rules ever says "okay, that's enough." Almost 9 out of 10 people surveyed had no idea.

One piece of good news; your prescription costs under Part D do have a yearly limit now. Doctor and hospital bills don't.

Medicare pays 80 cents on the dollar and you pay the rest

For most doctor visits, tests, and outpatient care, Medicare pays 80 percent of what it decides the care is worth. The other 20 percent is yours. More than 8 out of 10 people who were close to turning 65 didn't know that.

Twenty percent doesn't sound like much until you put a real number on it. If you have a surgery that runs $60,000, your share is $12,000. And because of what I just told you above, there's nothing that caps it there.

Signing up late for Part B follows you the rest of your life

Part B is the piece that covers doctors and outpatient care, and you pay for it every month. If you could have signed up and you didn't, and you weren't still working with health insurance from your job, Medicare adds 10 percent to that monthly cost for every full year you waited. It's not a one-time fine. It stays on the bill for good. Wait three years and you're paying 30 percent more, every month, forever. Almost 9 out of 10 people didn't know.

Drug coverage works the same way

Part D is your prescription coverage, and it has its own late penalty. Skip it when you're first able to sign up, without other drug coverage that counts, and you'll pay extra every month for as long as you have a drug plan.

I understand why people skip it. You're 65, you're not taking anything, and paying for a drug plan you don't use feels silly. Then something happens at 72 and you're paying for the plan plus a penalty you can never get rid of. Eight out of 10 people didn't know that was coming.

The door on a Medigap plan closes and doesn't open again

A Medigap plan, sometimes called a Medicare supplement, is what picks up that 20 percent I mentioned. Here's what catches people. You get one six-month window, and it starts the month you turn 65 and have Part B. During those six months, a company has to sell you a plan. They can't look at your health and turn you down.

Once that window closes, in most states, they can. They can also say yes and charge you a lot more because of your health history. About 7 out of 10 people didn't know there was a deadline at all. So the plan you'd want most, right when you get sick, may be the one you can no longer buy.

What to do about it

If you're 63 or 64, put your Part B date on the calendar today. Your window opens three months before the month you turn 65.

If you're already on Medicare and you don't have a Medigap plan or a Medicare Advantage plan, sit down and figure out what your 20 percent would look like on a big bill. It's a much better question to answer now than in a hospital room.

If somebody in your family is turning 65 this year, forward this to them. Every one of these penalties is avoidable, and none of them can be undone.

And if you're reading this and you already missed one of these deadlines, don't spend the night beating yourself up over it. Every state has free Medicare counselors through a program called SHIP. They don't sell anything and they don't work on commission. Call them and find out what you've still got available to you.

Nobody is going to call and remind you about any of this. That's what I'm here for.

— April

Source: eHealth survey of 1,000 Americans, August 2026, reported by Fierce Healthcare: https://www.fiercehealthcare.com/payers/many-medicare-beneficiaries-are-confident-they-understand-program-theyre-wrong-new-study