Roughly 34 million Americans are now enrolled in Medicare Advantage, according to federal data, while millions more stick with original Medicare plus a Medigap supplement.
The gap between those two paths shows up in ways that rarely make the marketing brochures: a $0 premium on one side, a $200 monthly bill on the other, and wildly different costs when you actually get sick.
Medicare Advantage works like an all-in-one bundle.
Private insurers run it, often with no premium beyond the standard Part B charge, and many plans throw in dental, vision, hearing, and gym perks.
You generally stay inside the plan's doctors and hospitals, and referrals may be required to see a specialist.
Costs come as copays and coinsurance each time you use care, and there is an annual out-of-pocket ceiling that changes every year.
A Medigap supplement is the opposite setup.
You keep original Medicare, which means any provider in the country who accepts Medicare is open to you, no referrals needed.
The trade-off is the premium, which can run well over $150 a month depending on your age, state, and plan letter.
In exchange, many plans cover most or all of the 20% that original Medicare leaves on you, turning unpredictable bills into a predictable monthly cost.
Here is where the math gets uncomfortable.
A healthy 65-year-old may save real money on Medicare Advantage for years, because premiums stay low and doctor visits are rare.
Then a cancer diagnosis or a broken hip arrives, and the copays stack up fast.
Advantage plans cap total spending, but that cap can still land in the thousands annually, and care often has to stay in network.
A supplement holder in the same situation may pay almost nothing beyond the premium they were already paying.
Switching later is the trap few people see coming.
In most states, Medigap insurers can ask health questions once you are past your initial enrollment window.
Get diagnosed with diabetes or heart disease, and you can be denied coverage outright.
Some states, including New York and Connecticut, offer year-round guaranteed acceptance, but most do not.
That means the choice at 65 can quietly lock in your options for decades.
The practical move is to price both paths with your actual medications and doctors in hand.
Call your current physicians and ask which Advantage plans they accept, then compare the annual out-of-pocket maximum against what a supplement would cost you over twelve months.
If you travel often or have ongoing specialists, the flexibility of original Medicare plus a supplement tends to earn its premium.
If you are healthy, live near a strong network, and want the lowest possible monthly bill, Advantage can make sense.
Open enrollment runs October 15 through December 7 each year, and Advantage members can also switch to another Advantage plan or back to original Medicare during that window.
Moving from original Medicare to Advantage is usually easy.
Moving back the other way is where the health questions bite.
The system rewards people who decide early and research hard, and it punishes anyone who picks on premium alone.
Final Thoughts
Treat the monthly number as the starting point, not the finish line, and read the out-of-pocket cap like your budget depends on it, because eventually it might.