Every year, millions of Americans on Medicare face the same fork in the road, and the wrong turn can quietly drain a retirement account.
The two main paths are Medicare Advantage (Part C) and Medicare Supplement plans, also called Medigap.
They behave nothing alike when you actually get sick.
Medicare Advantage is run by private insurers who contract with the government.
You often get dental, vision, hearing, and a $0 or low monthly premium, which is why ads make it look like a steal.
You keep original Medicare and buy a supplemental policy from a private insurer that covers most of what Medicare doesn't, but you pay a monthly premium for it.
Here's the catch that rarely makes the commercial.
Advantage plans come with networks, prior authorizations, and annual out-of-pocket maximums that can run into the thousands.
A 2023 KFF analysis found that a small share of prior authorization denials get appealed, even though many appeals succeed.
Translation: people give up, and the insurer keeps the money.
Premiums can run $100 to $250 or more per month depending on your age, location, and plan letter, and they rise over time.
But once you're in, most plans cover the 20% that Medicare leaves on your tab, and you can see any provider who takes Medicare nationwide.
During your six-month Medigap Open Enrollment window, starting when you're 65 and enrolled in Part B, insurers generally must sell you any policy regardless of health history.
Miss that window, and in most states you can be denied or charged more because of pre-existing conditions.
Switch from Advantage back to Medigap later, and you may face medical underwriting.
If you're healthy, travel little, and want the lowest monthly cost, Advantage can work.
If you have chronic conditions, see specialists, or want predictable costs, Medigap often pays off, especially once hospital stays enter the picture.
The "$0 premium" pitch ignores the bills that show up later.
The celebrity-filled ads and mailers are paid for by brokers who earn commissions, and Advantage plans tend to pay higher ones.
That doesn't make the advice wrong, but you should know who's getting paid when someone tells you which plan to pick.
Check each plan's star rating, drug formulary, and provider list yourself.
One more thing worth checking: the Medicare Plan Finder at medicare.gov lets you compare actual costs, not just premiums.
Enter your drugs and doctors and see what each option would really cost you.
The honest answer is that neither option is universally better.
The plan that fits your health, your doctors, and your budget this year may not fit next year, so review it every fall during open enrollment rather than letting it auto-renew on autopilot.
Our take: the "$0 premium" Advantage pitch is a marketing triumph, not a financial plan.
Run your own numbers, confirm your doctors are in-network, and treat any salesperson's recommendation with the skepticism it deserves.
Final Thoughts
The cheapest plan on the mailer is rarely the cheapest plan for your life.