Medicare's annual enrollment window is open through December 7, and roughly 68 million Americans are staring at the same fork in the road: stick with Original Medicare plus a supplement, or switch to a Medicare Advantage plan with its tempting $0 premium ads.
Advantage plans often advertise zero-dollar monthly premiums, while Medigap supplements can run $100 to $250 a month depending on your age, ZIP code, and health history.
That difference alone can add up to $2,000 or more per year — real money for households already stretched by grocery bills and rent.
But the cheap sticker price hides the part that bites later.
Advantage plans cap your annual out-of-pocket spending, yet those caps can reach $8,850 for in-network care in 2025, and more if you go out of network.
A supplement, by contrast, typically picks up nearly all of what Original Medicare doesn't — leaving you with few surprises beyond the premium itself.
Medigap insurers in most states can reject you or charge more based on health history once you're past your one-time guaranteed enrollment window.
If you have a chronic condition, a supplement may be the safer bet — but only if you can qualify and afford it today.
Doctors, hospitals, and specialists usually need to be in-network, and referrals are often required.
If you travel a lot or split time between states, that restriction can turn a routine specialist visit into a billing headache.
Here's the part that trips people up: switching back isn't easy.
Leave a supplement for an Advantage plan, then try to return a few years later, and you may face medical underwriting — or be denied outright.
That one-way door is why advisors say the choice matters more than the monthly number.
If you're healthy, cost-conscious, and comfortable with a network, an Advantage plan can work well.
If you want predictability and can handle the premium, a supplement often wins over the long haul — especially as medical needs grow.
Before December 7, do three things: list your doctors and check them against each plan's network, estimate your worst-case annual costs, not just the premium, and call your state's Senior Health Insurance Program for free counseling.
An hour of homework now beats a five-figure surprise later.
Our take: the $0 premium is a marketing hook, not a verdict.
Final Thoughts
Run your own numbers for your own health and budget — the plan that saves your neighbor money could quietly cost you thousands.