CSG Medicare Pros AZ offers comprehensive guidance on Medicare Enrollment and Qualifications. U.S. citizens or permanent residents over the age of 65 are eligible for Medicare. It is advisable to consider enrollment before reaching 65, with the Initial Enrollment Period starting three months prior to your 65th birthday and extending three months after. Missing this window may result in higher premiums for Part B. Those employed or covered under a spouse's employer can opt for a Special Enrollment Period post-65. The Annual Enrollment Period runs from October 15th to December 7th, allowing changes to Medicare Advantage and Part D plans. Additionally, the Open Enrollment Period from January 1st to March 31st permits modifications to Medicare Advantage plans or a switch back to Original Medicare with an added Part D plan. Outside these periods, changes to Medicare Supplement plans are permissible anytime, provided there is no current enrollment in a Medicare Advantage plan. Professional assistance is recommended to navigate these options effectively.