The majority of people join in Part A and Part B in the 7 months prior to, after, and three months after their 65th birthday, but some people may postpone enrollment if they intend to retire before that age. On the other hand, those who have been receiving Social Security Disability benefits for 24 months or who have certain medical conditions, such as ESRD and Amyotrophic Lateral Sclerosis (ALS), may enrol in Medicare before turning 65.