In the United States, eligibility for Social Security retirement benefits and Medicare begins at different ages depending on your specific situation. For Social Security retirement benefits, your full retirement age (FRA) ranges from 66 to 67, depending on your birth year. You can claim reduced benefits as early as age 62, though this results in permanently lower monthly payments. If you delay claiming past your full retirement age up to age 70, your benefit amount increases. For Medicare, eligibility generally begins at age 65, regardless of your Social Security claiming age. However, some people become eligible earlier: those with end-stage renal disease, permanent disabilities, or amyotrophic lateral sclerosis (ALS) can qualify before 65. You should enroll in Medicare when you first become eligible, even if you're still working, to avoid potential penalties. It's important to note that Social Security and Medicare are separate programs with different age requirements. Understanding your personal FRA is crucial because it affects how much you'll receive in lifetime benefits—claiming early reduces benefits permanently, while delaying increases them. Visit ssa.gov for your specific retirement age and to estimate your benefits.