With Medicare Parts A and B, you’re required to pay deductibles and coinsurance for Medicare-provided services. Medicare Supplement plans are designed to help pay for costs like deductibles, copayments, and coinsurance that you would typically pay out of your own pocket. The costs and benefits will depend on which Medicare Supplement plan you select. Here are a few more reasons to enroll in a Medicare Supplement plan: It helps pay the portion of approved expenses not covered by Medicare. Coverage is guaranteed if you enroll in the first six months of Medicare Part B eligibility Coverage is guaranteed to renew each year (unless you fail to pay premiums, make untrue statements, or commit fraud).