Every fall, millions of Americans sit down with a stack of Medicare mail and try to pick between two options that sound almost identical.
One is Medicare Advantage, the all-in-one plan run by private insurers.
The other is a Medicare Supplement plan, often called Medigap, which fills the gaps in original Medicare.
The pitch for Advantage is irresistible: low or $0 monthly premiums, dental, vision, gym memberships.
The pitch for Medigap is boring: higher monthly premiums, fewer extras, but you can see almost any doctor who takes Medicare.
You generally stay in a network, and you may need referrals or prior authorization before certain procedures.
Denials happen, and a 2023 federal report found some insurers were denying requests that should have been approved.
Medigap has no networks beyond Medicare itself.
If a doctor accepts Medicare, they accept you.
The cost math is where it gets uncomfortable.
Advantage premiums can look cheap, but out-of-pocket costs can climb.
In 2024, Advantage enrollees faced a maximum out-of-pocket limit that could reach $8,850 for in-network care, and higher if you go out of network.
Medigap Plan G, the most popular option, covers nearly everything after a small deductible, but you pay a monthly premium that varies by state, age, and insurer.
Insurance companies earn more when you pick Advantage, because they receive a fixed payment from the government per enrollee and keep what they don't spend on care.
That's not automatically bad, but it explains the flood of ads, the free dinners, and the celebrity spokespeople.
Medigap agents earn commissions too, but the plans are standardized by letter, so shopping is mostly about price and rate history.
There is one rule that matters more than any other.
When you first enroll in Medicare Part B, you get a six-month Medigap open enrollment window.
During that time, insurers generally cannot reject you or charge more because of health conditions.
Miss it, and in most states you can be denied or charged more later.
Advantage has annual open enrollment, so switching into it is easy.
Check whether your doctors and hospitals are in an Advantage network before you sign up.
Add up premiums plus worst-case out-of-pocket costs for both options, not just the monthly number.
If you travel a lot or have ongoing health issues, Medigap often pencils out better.
If you're healthy, cost-focused, and comfortable with networks, Advantage can work.
Read the formulary, the prior authorization rules, and the star ratings.
Call your doctors' offices and ask what they actually accept.
The plan brochures won't tell you which one is right for you, because they're designed to sell, not to compare.
The real problem isn't that either option is a scam.
It's that the choice is made once, often quickly, and the consequences can lock in for years.
The system rewards insurers for complexity, and complexity is exactly what a 75-year-old on a fixed income shouldn't have to decode alone.
Final Thoughts
Bring someone you trust to the kitchen table, do the math, and treat the sales pitch as a starting point, not an answer.