If you're turning 65 this year, your mailbox is probably stuffed with promises of $0 premiums, free dental, and grocery allowances.
Those ads are selling Medicare Advantage.
What they rarely mention is the trade-off buried in the fine print: narrow doctor networks and prior authorization requests that can delay or deny care.
You pay the government's 20% share yourself unless you buy a Medigap supplement plan, which picks up most of the rest.
In exchange, you can see almost any provider in the country who accepts Medicare, and you generally don't need permission before treatment.
A Medigap Plan G can run $120 to $200 per month depending on your age and state, on top of the standard Part B premium—$185 in 2025.
Advantage plans often advertise $0 premiums, but they come with copays, and the average out-of-pocket limit sits near $5,000 to $8,000 a year if you get seriously sick.
Here's the trap few people explain clearly.
When you first enroll in Medicare, you get a one-time Medigap open enrollment window that lasts six months.
During that window, insurers must sell you a supplement regardless of your health history.
Miss it, and you may face medical underwriting later—meaning a cancer diagnosis or heart condition could make you uninsurable for Medigap in most states.
That's why switching from Advantage back to a supplement gets hard after the first year.
You can usually return to traditional Medicare, but the supplement may be priced out of reach or denied outright.
Consumer advocates call this the "roach motel" problem: easy to check in, tough to check out.
If you're healthy, take few prescriptions, and want dental, vision, and hearing bundled in, the lower monthly cost can work in your favor.
Some plans also offer fitness memberships and over-the-counter allowances that stretch a fixed income.
The math flips fast when your health changes.
One hospital stay, a skilled nursing stint, or a course of chemotherapy can push you toward that annual out-of-pocket maximum.
At that point, the supplement you skipped at 65 can look like the bargain of a lifetime.
If you're still deciding, do three things.
Check whether your doctors and hospital are in the plan's network.
List your prescriptions and price them under both options, including the Part D drug coverage.
Then ask a state-licensed counselor through your local SHIP office—free, unbiased help that doesn't earn a commission on what you choose.
Our take: treat Medigap as insurance against worst-case scenarios, not a monthly bill to minimize.
If you can afford the premium and you're in your initial enrollment window, locking in that protection is usually the safer bet.
Final Thoughts
Advantage plans are a budget tool, not a safety net—and the difference only becomes obvious when you actually need care.