You become eligible for Medicare at age 65 (younger if you have a disability), which is when most companies and individuals stop paying the premiums for a comprehensive private health plan. You have a seven-month window to sign up, starting three months before your 65th birthday. If you delay beyond this time period, you may incur penalties. You can enroll directly by contacting the Social Security Administration. You also have the option of enrolling through a private insurer that offers a Medicare Advantage plan, which is basic Medicare plus a few extra bells and whistles like dental and vision benefits. You can get free answers to any questions through your State Health Insurance Assistance Program, which you can find at hapnetwork.org/ship-locator.