1. Confirm your starting point
- Your date of birth and expected 65th-birthday month.
- Whether you receive Social Security or Railroad Retirement benefits.
- Whether Medicare has already sent an enrollment notice or card.
- Whether eligibility is based on disability, ALS, or End-Stage Renal Disease rather than age.
2. Review existing insurance
- Name of the employer and insurer.
- Whether coverage is based on current employment.
- Employment and coverage end dates.
- Employer benefits contact information.
- Whether you contribute to a Health Savings Account.
3. Identify the filing route
- Initial application for Part A and Part B, or Part A only.
- Part B-only Special Enrollment Period application.
- General Enrollment Period application when no other period applies.
- Railroad Retirement Board process, when applicable.
4. Prepare supporting records
- Social Security number and basic identity information.
- Current health insurance information.
- CMS-40B and CMS-L564 when required for Part B enrollment after employer coverage.
- Evidence requested by Social Security for an exceptional Special Enrollment Period.
5. Save after filing
- Application confirmation.
- Copies of forms and employer evidence.
- Enrollment notice and effective date.
- Medicare number and card once issued.
Premium notice after enrollment
- Review any Social Security notice that adds IRMAA to Part B or Part D.
- Keep the tax year and filing status used in the determination.
- If a listed life-changing event reduced income, review the current SSA-44 route.
- Do not confuse IRMAA with a late-enrollment penalty or a state Medicare Savings Program.
Use the SSA-44 IRMAA checklist.