Location is everything, especially when it comes to insurance that's supposed to supplement your Medicare coverage.
Medigap is a form of insurance that will fill in for the areas where your own Medicare policy may fall short, such as deductibles, copayments and coinsurance. Some policies cover certain extras, like medical care when you're traveling outside of the U.S.
Medigap supplements Medicare parts A and B, which cover hospital and physician's visits. Medigap plans offer an array of different benefits that will vary and are distinguished by letter (A, B, C, D, F, G, K, L, M and N).
Federal law requires that you get a six-month period from when you first enroll in Medicare to buy a Medigap policy and do so without the insurance company digging into your health history and sticking you with higher premiums because of your medical conditions.
Federal law also includes guaranteed renewability on Medigap policies, meaning that as long as you pay your premiums, the insurer can't cancel your coverage.
There are a handful of other situations in which a retiree may not be denied Medigap coverage; for instance, in the event you have Medicare and retiree health-care coverage through work and that employer plan is ending.