If you're turning 65 this year, you're about to get buried in mailers promising free dental, free groceries, and a plan that "pays everything." Before you pick, understand that Medicare Advantage and Medicare Supplement are two completely different animals, and choosing wrong can lock you into costs you didn't see coming.
Original Medicare covers about 80% of most medical costs.
A Medicare Supplement plan, also called Medigap, picks up most of that remaining 20%.
There are no networks, no referrals, and you can see any doctor in the country who accepts Medicare.
Depending on your state and age, Medigap can run $100 to $250 or more per month on top of your Part B premium.
Medicare Advantage works more like an HMO or PPO from an employer.
You often pay a $0 premium, but you agree to use the plan's network and follow its rules.
Copays for specialists, hospital stays, and even some drugs can add up fast.
Many plans cap your yearly out-of-pocket spending, which sounds great until you realize that cap can sit around $8,000 or more.
When you first enroll in Medicare, you get a one-time open enrollment window, usually six months, when you can buy any Medigap plan regardless of your health history.
Miss that window and insurers in most states can ask about your conditions and charge you more, or turn you down entirely.
That single deadline is why advisors say the Medigap decision is the one you can't easily undo.
Medicare Advantage has its own escape hatch.
Every year from January 1 to March 31, you can drop an Advantage plan and switch to Original Medicare.
But here's the trap: switching back to Medigap later usually means passing medical underwriting.
A cancer diagnosis, diabetes, or even a treated heart condition can block you from the very coverage you want once you need it most.
If you have a chronic condition, travel a lot, or want predictable costs and full doctor access, Medigap plus a standalone Part D drug plan tends to be the safer long-term bet.
If you're healthy, live on a fixed income, and value extras like dental, vision, and gym memberships, an Advantage plan can work well, as long as you read the fine print on networks and copays.
Run the math on your actual medications and doctors before you decide.
A plan that looks free on the brochure can cost thousands once you use it.
And if you're already in an Advantage plan and thinking about switching, do it before your health changes, not after.
The bottom line is that cheap upfront rarely means cheap overall.
Medicare is one of the few purchases in your life where the higher monthly premium can save you real money later.
Final Thoughts
Pick based on your health and your doctors, not the flashiest mailer in your stack.