10 things to know about Medigap and Medicare Supplement policies.

1. You must have Medicare Part A and Part B.
2. A Medigap policy is different from a Medicare Advantage plan. Original Medicare and Medicare Advantage plans are ways to get Medicare benefits, while a Medigap policy from private insurers only supplements your original Medicare Parts A and B benefits.
3. You pay the private insurance company a monthly premium for your Medigap or Supplement policy. You pay this monthly premium in addition to the monthly Part B premium that you pay to Medicare and any Part D prescription drug premium that you may pay.
4. A Medigap or Supplement policy only covers one person. If you and your spouse both want Medigap or Supplement coverage, you'll each have to buy separate policies.
5. You can buy a Medigap or Supplement policy from any insurance company that's licensed in your state to sell one.
6. It's important to compare Medigap or Supplement policies since the costs can vary between plans offered by different companies for the same coverage and may go up as you get older. Most states limit Medigap or Supplement premium costs.
7. Any standardized Medigap or Supplement policy is guaranteed to be renewable, even if you have health problems. This means the insurance company can't cancel your Medigap or Supplement policy as long as you pay the premium.
8. Medigap Supplement Insurance can no longer be sold with drug coverage; however, if you have an older Medigap or Supplement policy that was sold with drug coverage (before January 1, 2006), you can keep that particular supplement.
9. You may choose to join a separate Medicare Prescription Drug Plan (Part D) because Medigap or Supplement drug coverage may not be considered creditable prescription drug coverage. You may pay more if you join Medicare Part D (prescription drugs) when the penalty for not joining Medicare Part D begins.
10. If you buy a Medigap or Supplement and a Medicare drug plan from the same company, you may need to make two separate premium payments. Contact the company to find out how to pay your premiums.

It's illegal for anyone to sell you a Medigap or Supplement policy if you currently have a Medicare Advantage Plan, unless you're switching back to Original Medicare Parts A and B.