For about 23% of Medicare's 65.1 million beneficiaries, the solution for covering those outlays is a so-called Medigap plan. The reasons that some beneficiaries instead choose Medigap alongside basic Medicare vary from person to person, according to Elizabeth Gavino, founder of Lewin & Gavino and an independent broker and general agent for Medicare plans. watch nowHere's what to know about Medigap policies if you're considering purchasing one. There's huge variation in costDespite Medigap policies' standardization, the premiums can vary greatly. The way a Medigap plan is 'rated' also mattersAnother difference in Medigap premiums can come from how the plans are "rated."

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