Medicare is a federal health insurance program that caters to individuals 65 and older, people with disabilities, or those with End-Stage Renal Disease. The goal of Medicare is to make medical costs for these groups of people more affordable. However, there are many rules and limitations that come with medicare, which will be covered below. How Does Medicare Work? At a basic level, to receive Medicare, an individual must be 65 or older and have been a U.S. citizen or permanent legal resident for a certain amount of time. As mentioned, other groups that are eligible include those who receive Social Security disability Insurance or have certain illnesses. Those who have reached 65 or older have a rigid window to sign up for coverage – that period is called an initial enrollment period. If that window is missed, it can lead to long wait times, gaps in coverage, or late enrollment penalties. There are exceptions to these rules, which can be found on the Social Security’s website. Outside of the initial enrollment period, people can sign up for medicare and switch plans during open enrollment.