If you're 65 or older, you've probably been buried in Medicare mail.
The envelopes promise dental, vision, gym memberships, even grocery cards.
Fewer mention the alternative: original Medicare paired with a supplement plan.
They work very differently when you actually get sick.
Medicare Advantage, known as Part C, is run by private insurers.
You stay in the program, but the company manages your care, usually through networks of doctors and hospitals.
Many plans charge $0 premiums and throw in extras.
Original Medicare plus a Medigap supplement works more like traditional insurance: the government pays its share, the supplement covers most of what's left, and you can see almost any provider in the country who accepts Medicare.
Advantage plans tend to have low monthly premiums but higher costs when you use care — copays for visits, hospital stays, and procedures.
You pay a monthly premium, often $100 to $200 or more depending on your state and age, but your out-of-pocket costs shrink dramatically.
Katy Votava, a Medicare researcher and author, told me the gap can run into thousands of dollars a year for people with serious conditions.
Cancer treatment, joint replacements, and long hospital stays are where the difference bites hardest.
Advantage plans do cap annual out-of-pocket spending, but those caps can run north of $8,000 for in-network care, and more if you go outside the network.
Votava also warns that Advantage plans use prior authorization — the insurer must approve certain tests, drugs, and procedures before you get them.
Denials are common and appeals take time.
Supplements don't require prior authorization for Medicare-covered services.
In most states, Medigap insurers can reject you or charge more based on your health history after your initial enrollment window.
If you start with Advantage and later get diagnosed with something expensive, you may not be able to move to a supplement at any reasonable price.
A handful of states, including New York and Connecticut, offer more flexibility, but most don't.
If you're healthy, take few prescriptions, and want predictable low premiums, they can work.
The extras — dental, hearing aids, fitness — are genuine value for some households.
And some plans rate well on quality measures.
The enrollment period for 2025 coverage runs through December 7.
If you're already in a plan, check whether your doctors and prescriptions are still covered.
Formularies and networks change every year, and that letter you tossed in October may have bad news inside.
Here's the part nobody puts on a brochure: the choice you make at 65 often locks in your options for life.
That's not a sales pitch — it's how Medigap underwriting works in most states.
If you can afford a supplement, the long game usually favors it.
Final Thoughts
If you can't, go into an Advantage plan with your eyes open about what you'll owe when you actually need care.