Medicare's annual open enrollment runs through December 7, and roughly 68 million Americans are making a choice that can swing their health costs by thousands of dollars a year.
The two main paths—Medicare Advantage and Medicare Supplement—look similar on a brochure but behave nothing alike when the bills arrive.
Medicare Advantage, known as Part C, is the all-in-one option.
Private insurers bundle hospital, medical, and usually drug coverage into one plan, often with a $0 premium on top of the standard Part B charge.
The trade-off shows up later as copays, coinsurance, and prior authorizations that can delay or deny care.
Medicare Supplement, also called Medigap, works the opposite way.
You keep Original Medicare and buy a private policy that covers most of what Medicare leaves behind—deductibles, coinsurance, the 20% that never goes away.
Premiums run higher, often $100 to $250 a month depending on your state and age.
The math matters more now because the standard Part B premium for 2024 sits at $174.70 a month, and Advantage plans increasingly lean on extra benefits like dental, vision, and grocery allowances to compete.
Those perks are real, but they can change every year.
A plan that covers your hearing aids in January may drop them by the next enrollment window.
The most dangerous gap is the out-of-pocket maximum.
Advantage plans cap annual spending, but those caps can reach $8,850 for in-network care in 2024, and out-of-network costs can run higher.
A bad year with a hospital stay, a cancer diagnosis, or a specialist-heavy condition can push a household toward that ceiling fast.
Medigap plans typically leave you with little beyond the Part B premium.
There is a catch that traps people every year: Medigap insurers in most states can reject you or charge more based on health history after your initial enrollment window closes.
Switch from Advantage to a supplement later, and you may face medical underwriting.
That is why the original decision carries so much weight.
Advantage plans do win on price for healthy retirees who rarely see doctors and want predictable monthly costs.
They also win on extras—gym memberships, over-the-counter allowances, transportation.
For someone managing a chronic condition or facing surgery, the flexibility of Original Medicare plus a supplement often costs less in a bad year, even with the higher premium.
The practical move is to price your actual medications and doctors, not the marketing.
Check whether your physicians are in-network, whether your drugs sit on the formulary, and what the plan's star rating says about denials.
Then compare the worst-case year, not the best-case one.
Medicare Advantage enrollees can switch plans or return to Original Medicare during the Medicare Advantage Open Enrollment Period from January 1 to March 31—but buying a Medigap policy at that point may still require passing underwriting. **Our take:** The cheaper premium is rarely the cheaper plan once you use it.
Retirees who treat this as a budget line item instead of a medical decision are the ones who get burned.
Final Thoughts
Run your own numbers, and if you have any ongoing condition, assume you will need the care.