Medicare Starter Guide: What to do in Your First 90 Days

Understanding the Initial Enrollment Period (IEP)

Your Initial Enrollment Period (IEP) is a 7-month window centered on your 65th birthday: 3 months before, the month of, and 3 months after. This is your primary window to enroll in Medicare Parts A and B, and it is also when your Medigap Open Enrollment Period begins (once Part B starts).

The timing of your enrollment within the IEP determines when your coverage starts. If you enroll during the three months before your birthday month, coverage begins the first day of your birthday month. If you enroll during your birthday month or later, coverage may be delayed by one to three months. Planning ahead prevents gaps in coverage.

Confirming Your Medicare Start Date

Log in to MyMedicare.gov or call 1-800-MEDICARE to confirm your Part A and Part B effective dates. Your Medicare card should arrive in the mail about 3 months before your 65th birthday if you are already receiving Social Security benefits. If not, you will need to actively enroll through SSA.gov or your local Social Security office.

Once you have your card, verify that your name, Medicare number, and coverage dates are correct. Report any errors immediately to Social Security. Keep a photo of your card on your phone and store the original in a safe place. You will need your Medicare number when enrolling in supplemental coverage.

Choosing the Right Medicare Plan

You have two main paths: (1) Original Medicare (Parts A and B) plus a Medigap supplement and Part D drug plan, or (2) Medicare Advantage (Part C), which bundles A, B, and usually D. Each has trade-offs in cost, flexibility, and coverage. The first 90 days is the ideal time to make this decision while you have guaranteed issue rights for Medigap.

If you choose Original Medicare with a Medigap plan, you get the freedom to see any doctor who accepts Medicare nationwide, with predictable out-of-pocket costs. If you choose Medicare Advantage, you may pay lower premiums but will be limited to a provider network and may face prior authorization requirements. This decision is difficult to reverse later because switching from Advantage back to Original Medicare after your first year typically requires medical underwriting for Medigap.

Signing Up for Additional Coverage

1. Enroll in a Medigap plan during your 6-month Open Enrollment Period (guaranteed issue, no health questions)

2. Enroll in a Part D prescription drug plan to avoid the late enrollment penalty (1% of the national base premium per month for every month you delay)

3. Schedule your Welcome to Medicare preventive visit (covered at no cost in your first 12 months)

4. Set up your MyMedicare.gov account to track claims, coverage, and preventive service eligibility

5. Review your Medicare Summary Notices (MSNs) for accuracy and watch for billing errors

6. Consider dental, vision, and hearing coverage, which Original Medicare does not cover

Understanding Medicare Costs in 2026

Knowing what you will pay out of pocket helps you budget and choose the right supplemental coverage. Here are the standard 2026 Medicare costs:

Without supplemental coverage, a single hospital stay could cost you $1,736 for the deductible plus 20% of doctor charges. A Medigap Plan G, for example, covers everything except the Part B deductible, meaning your maximum annual exposure is just $283 plus your monthly premiums.

What Changed for 2026

Several important changes took effect that directly impact new Medicare beneficiaries in 2026:

• The Part D out-of-pocket cap remains at $2,000 per year, meaning no beneficiary pays more than $2,000 for covered drugs annually regardless of how expensive their medications are

• The Medicare Prescription Payment Plan allows you to spread your Part D out-of-pocket costs into monthly installments throughout the year instead of paying large amounts at the pharmacy

• Part B premium increased to $202.90 per month (up from $185.00 in 2025)

• The Part A hospital deductible increased to $1,736 per benefit period (up from $1,676 in 2025)

• IRMAA income brackets have been adjusted, so check whether your income triggers higher premiums

Your 90-Day Medicare Checklist

Use this week-by-week timeline to stay on track during your first 90 days:

Do not wait until the end of your 90 days to start this process. Medigap carriers take time to process applications, and you want coverage in place before you need it. Starting in the first two weeks gives you a comfortable buffer.

Common Mistakes in Your First 90 Days

After helping thousands of new Medicare beneficiaries, these are the most costly mistakes we see:

• Delaying Medigap enrollment past the 6-month Open Enrollment Period. After this window closes, carriers can deny you or charge higher rates based on your health history.

• Skipping Part D enrollment because you do not take medications now. The late enrollment penalty accumulates for every month you go without creditable drug coverage and lasts for as long as you have Part D.

• Choosing Medicare Advantage without understanding the network restrictions. If you travel frequently or want to see specialists without referrals, Original Medicare with Medigap may be a better fit.

• Not scheduling the Welcome to Medicare visit. This free preventive exam is only available in your first 12 months and establishes a health baseline that can catch issues early.

• Assuming employer coverage automatically coordinates with Medicare. If you or your spouse are still working, the rules for how Medicare interacts with employer plans depend on employer size and your specific situation.

• Ignoring IRMAA. If your modified adjusted gross income from two years ago exceeds certain thresholds, you will pay higher Part B and Part D premiums. Plan ahead if you had a high-income year before retiring.

Frequently Asked Questions