Every fall, millions of American retirees sit down with a stack of Medicare mail and a decision that can swing their out-of-pocket costs by thousands of dollars a year.
On one side: Medicare Advantage, the all-in-one private plans that often advertise $0 premiums and free gym memberships.
On the other: Medigap supplements, which cost real money every month but quietly pick up most of what original Medicare leaves behind.
The sales pitch for Advantage is loud and everywhere.
The pitch for supplements is usually a plain envelope and a paragraph of fine print.
That asymmetry alone should make you suspicious.
Original Medicare pays 80% of most covered costs and leaves you the other 20% with no ceiling.
A Medigap plan covers most or all of that gap, so a hospital stay doesn't turn into a second mortgage.
Medicare Advantage instead gives you one card, often extras like dental or vision, and a network you generally have to stay inside.
The tradeoff is prior authorizations, referrals, and copays that can add up fast if you get seriously sick.
Insurers spend heavily pushing Advantage because those plans are lucrative, and Uncle Sam pays them a set amount per member.
That doesn't make them bad, but it does mean the free-lunch framing deserves scrutiny.
So is the specialist who suddenly needs approval.
Costs are where the math gets uncomfortable.
A Medigap Plan G for a 65-year-old can run well over $100 a month, sometimes several hundred depending on the state and insurer.
Advantage plans can carry a $0 premium but a hospital copay per stay, a daily charge for extended care, and a yearly out-of-pocket maximum that can still sting.
In a healthy year, Advantage often wins on price.
The trap many people miss: switching later isn't always possible.
In most states, once you leave original Medicare for Advantage, Medigap insurers can medically underwrite you when you try to come back.
A cancer diagnosis or a new heart condition can make that supplement unaffordable or flatly unavailable.
You can usually move from a supplement to Advantage, but the reverse door is often locked.
So the real question isn't which plan is cheaper this month.
It's how much uncertainty you can absorb.
If you can comfortably handle the premium and want predictable costs, a supplement buys peace of mind and freedom to see almost any doctor who takes Medicare.
If the premium is genuinely out of reach, Advantage can be a reasonable lifeline, as long as you read the network rules and the annual out-of-pocket cap before you sign.
Watch the details that decide it: whether your doctors are in-network, whether your prescriptions are covered, and whether the plan changes its formulary next year.
Advantage plans can alter coverage annually, and that letter in the mail is not junk. **Our take:** The heavily advertised option isn't automatically the better one, and the boring envelope isn't automatically the worse one.
Run your own numbers for a bad health year, not just a good one, and ask who profits from the plan you're being sold.
Final Thoughts
If the answer isn't obvious, that's your cue to slow down and read.