You must be enrolled in both Medicare Part A and Part B to buy a Medicare Supplement (Medigap) policy. Medigap policies cover one person, so spouses each need their own policy.

The best time to buy is during your Medigap Open Enrollment Period. This 6-month period starts the first month you are both 65 or older and enrolled in Medicare Part B. During it, an insurance company cannot refuse to sell you any Medigap policy it offers or charge you more because of your health. If you apply after this period, the company may be able to use medical underwriting unless you qualify for a guaranteed issue right. If you have Medicare before 65 because of a disability or ESRD, you get a Medigap Open Enrollment Period when you turn 65.

No. You must be enrolled in both Medicare Part A and Part B to buy a Medicare Supplement policy. To learn how to sign up for Part A and Part B, contact Social Security at 1-800-772-1213 (TTY 1-800-325-0778) or visit ssa.gov. You can also call Medicare at 1-800-MEDICARE (1-800-633-4227), 24 hours a day, 7 days a week (TTY 1-877-486-2048).

Not everyone needs a Medicare Supplement policy. You probably do not need one if you are enrolled in a Medicare Advantage plan (it is illegal for anyone to sell you a Medigap policy while you have one), if Medicaid or the Qualified Medicare Beneficiary (QMB) Program pays your Medicare premiums and out-of-pocket costs, or if you have group health coverage from current employment.

Yes. Medicare Supplement plans do not require referrals, so you can see any doctor or specialist in the U.S. who accepts Medicare. Your costs can be lower if the doctor accepts Medicare assignment.