It's wise to purchase health insurance to supplement your Medicare coverage, because Medicare generally won't cover all of your medical expenses. Usually, you'll have to satisfy a deductible before Medicare pays anything, and you'll also pay a co-payment when you visit a physician or are admitted to the hospital.

Fortunately, you can buy supplemental insurance from private companies that will help you plug the gaps in your Medicare coverage. These Medigap plans are regulated and standardized by the federal government. There are 10 different kinds of plans, although your state may not offer all 10. If cost is a concern, you can purchase low-cost Medigap plans that offer coverage through managed care plans. Conversely, if you want extensive coverage and don't mind paying more for it, you can purchase a Medigap plan that covers most of the deductible, co-payments, prescription costs, and extra charges associated with Medicare. You can compare plans at the Health Care Financing Administration's website (www.medicare.gov).

Whatever plan you choose, you have the right to cancel it within a certain amount of time (usually 30 days, sometimes longer) if you don't like the policy after you buy it. In addition, the policy must be guaranteed renewable and cannot duplicate existing coverage, including Medicare.

Another way to supplement Medicare is to keep in effect any employer-sponsored health-care benefits. You'll submit claims first to your employer-sponsored plans and then to Medicare if any costs were not covered by the first plan.