You are eligible for premium-free Original Medicare Part A (hospital insurance) if you qualify for one of these situations: You are age 65 or older, and you or your spouse worked and paid Medicare taxes for at least 10 years. You are receiving retirement benefits from Social Security or the Railroad Retirement Board. You are eligible to receive Social Security or Railroad benefits, but you have not yet filed for them. You or your spouse had Medicare-covered government employment. If you fail to enroll for Part A during your initial enrollment period, you will have to wait until the open enrollment period that takes place Jan. 1 — March 31 each year with coverage starting July 1. Additionally, a premium will be included for Part A, even if you qualified for premium-free coverage, if you didn’t sign up when you were first eligible (and have no special enrollment period opportunities). Find your expected premium by using the Medicare.gov eligibility tool.