Those eligible for Medicare benefits include U.S. citizens or permanent residents who have earned enough work credits and are 65 and over, disabled, have end-stage renal disease or have Lou Gehrig's disease. Those otherwise qualified without enough work credits can purchase Medicare benefits by paying monthly premiums.
Individuals eligible for Medicare must be either U.S. citizens or permanent resident aliens who have lived in the United States for at least five years continuously. Those with enough work credits for Social Security benefits or railroad retirement benefits also qualify for Medicare. Benefits begin at age 65 for an employee and an employee's spouse, but if they are not already receiving Social Security or railroad benefits, they are not enrolled automatically and need to apply for Medicare. Disabled people can receive Medicare if they have been eligible for Social Security disability benefits for at least two years, collect a disability pension from the Railroad Retirement Board or have a qualifying disease.
Those with 40 or more work credits, which are earned in approximately 10 years of work, are eligible to receive Medicare Part A hospital insurance without cost, as of 2015. If they have less than 40 hours of work credits, they must pay for Medicare Part A coverage. All Medicare enrollees pay premiums for Medicare Part B medical coverage. Medicare Part C, also known as Medicare Advantage, and Medicare Part D prescription drug coverage are optional plans run by private Medicare-approved companies.