Who qualifies for Medicare supplemental insurance?

Medicare helps a lot but still leaves gaps—premiums, deductibles and coinsurance have risen, and Original Medicare has no annual out‑of‑pocket cap.
Medigap can fill many of those gaps but only works with Original Medicare (Parts A & B), not Medicare Advantage, and you get the strongest protections in the six‑month open‑enrollment window starting at 65.
Rules and availability vary by state (especially if you’re under 65), and Medigap won’t cover drugs, routine dental/vision or long‑term care—so compare plans and costs before you buy.