Every fall, your mailbox fills up with glossy promises: $0 premiums, dental, vision, even a gym membership.
What those ads conveniently leave out is the part where you might need a referral to see a specialist, or where the network suddenly doesn't include your cardiologist anymore.
Medicare Advantage (Part C) is run by private insurers who get paid a set amount per member.
Medigap, also called a supplement, is different — it picks up the costs Original Medicare doesn't cover, and you can see basically any provider who takes Medicare.
The trade-off is real, and it's mostly about money and control.
Advantage plans often come with low or zero monthly premiums but carry copays, annual out-of-pocket maximums that can run into the thousands, and prior authorization requirements that can delay or deny care.
Medigap plans charge a monthly premium that can rival a car payment, but once you're enrolled, the plan pays its share without haggling over whether you "really" needed that MRI.
Then there's the catch that trips up a lot of people: your window to buy Medigap is limited.
In most states, you get a six-month guaranteed-issue period when you first enroll in Part B at 65.
After that, insurers can ask about your health and charge you more — or reject you outright.
Switch from Advantage to Medigap a few years later, after a diagnosis, and you might find the door locked.
Advantage insurers, who spend heavily on marketing because a steady stream of members means steady federal payments.
Agents earn commissions either way, but the pitch for Advantage is louder because the low premium headline sells itself.
That doesn't make Advantage a scam — millions of people are happy with it, especially those who want extras and don't travel much.
But it does mean the sales pitch is optimized for sign-ups, not for your ten-year health trajectory.
A few practical checks before you decide.
Look up whether your doctors and hospital are in the specific plan's network, not just the insurer's.
Add up the worst-case out-of-pocket number, not just the premium.
And read the prior authorization list if you have any chronic condition.
If you can afford the Medigap premium and value flexibility, locking it in early is the move many financial planners recommend.
If cash flow is tight now and you're generally healthy, Advantage can work — just go in with your eyes open.
The real risk isn't picking the "wrong" plan.
It's picking based on a TV ad and a $0 premium, then discovering the rules at the worst possible moment.
My take: this decision deserves an afternoon of actual research, not a phone call from a stranger who called you first.
The plan that saves you $40 a month now can cost you far more later if it locks you out of the care you need.
Final Thoughts
Read the fine print before someone else's commission decides your coverage.