If you're turning 65 this year, you're about to make one of the most expensive decisions of your retirement.
The mailers are already piling up, the commercials promise free gym memberships and dental care, and somewhere in the fine print, your actual costs are hiding.
Medicare Advantage (Part C) is the all-in-one option: private insurers bundle your hospital, doctor, and drug coverage, often with a $0 monthly premium and extras like hearing aids or rides to appointments.
Original Medicare plus a Medigap supplement works differently—you pay a monthly premium for the supplement, but in exchange, the plan picks up most of what Medicare doesn't, and you can see any provider in the country who accepts Medicare.
The catch with Advantage plans isn't the premium.
Copays for specialists, labs, imaging, and hospital stays can stack up fast.
Out-of-pocket maximums are legally capped, but in 2025 that cap can run past $9,000 for in-network care—and higher if you go out of network.
A rough year with a cancer diagnosis or a broken hip can turn that "free" plan into a bill you feel for a decade.
You pay more every month—often $100 to $200 or more depending on your state and age—but your share of covered costs is usually tiny.
If you travel or split time between states, that flexibility alone can be worth the premium.
Then there's the fine print nobody reads until it bites.
Advantage plans often require prior authorization for procedures, and denials do happen.
Some plans have narrow networks that change year to year—your cardiologist might be in-network this January and out the next.
Supplements don't play that game, but they also don't cover dental, vision, or hearing, so you'd buy those separately.
When you first enroll in Medicare, you get a one-time Medigap open enrollment window—generally six months—when insurers must sell you a supplement regardless of your health history.
Miss it, and you can be denied or charged more because of pre-existing conditions in most states.
Advantage plans, by contrast, let you switch during annual enrollment, but switching back to a supplement later can be medically underwritten in most of the country.
It depends on your health, your budget, and your tolerance for surprises.
If you're healthy, want low premiums, and rarely see specialists, Advantage can work well.
If you have chronic conditions, travel, or simply want predictable costs, a supplement often pays for itself in one bad hospital stay.
One practical move: check whether your doctors and hospitals are in-network before you sign anything.
Call the billing office, not the insurer's sales line.
And compare the plan's out-of-pocket maximum against the supplement's annual premium plus deductible—that's the real price tag, not the number on the envelope. **The bottom line:** The cheapest plan today is rarely the cheapest plan over ten years.
Final Thoughts
Treat the open enrollment window like the deadline it is, because in most states, you don't get a second chance at the same price.