Health care is one of the largest expenses most retirees incur in their later years, and Medicare only covers a portion of heath care expenses. It is broken up into different parts. Part A is offered at no cost, but mainly covers only expenses related to hospitalization. Part B requires a monthly premium, but makes medical services such as care from a doctor or tests more affordable. Part C is an alternative type of Medicare coverage provided through private insurers, at a cost. Part D is a prescription program that helps reduce the price of drugs. Medicare Supplement coverage is another form of coverage that charges a premium, but helps reduce out-of-pocket medical expenses.