Key Takeaways

• You have a limited time to enroll in Medicare when you first become eligible, and missing this window can lead to penalties and delayed coverage.

• Understanding the basic structure of Medicare Parts A, B, C, and D in 2025 is essential to avoid coverage gaps and unnecessary costs.

Understanding the Medicare Enrollment Windows

Medicare doesn’t wait. If you become eligible and fail to act within your designated enrollment period, you risk penalties, delays, and even lapses in coverage. Here’s what you need to know in 2025:

Initial Enrollment Period (IEP)

This is your first opportunity to sign up for Medicare. The IEP spans 7 months:

• Begins 3 months before your 65th birthday

• Includes your birthday month

• Ends 3 months after your birthday month

If you enroll during the first three months, your coverage begins the month you turn 65. Enrolling later in the IEP can delay your coverage start date.

General Enrollment Period (GEP)

If you miss the IEP, the GEP runs from January 1 to March 31 each year. Coverage begins July 1. However, enrolling during the GEP can lead to late enrollment penalties:

• Part B: You may pay a 10% higher premium for each 12-month period you were eligible but didn’t enroll.

• Part A (if not premium-free): Penalties also apply and can last twice the number of years you didn’t sign up.

Special Enrollment Period (SEP)

You may qualify for an SEP if you delay Medicare because you had coverage through an employer. The SEP lasts for 8 months after that coverage ends. It allows you to avoid penalties, but timing is critical—especially for Part B and Part D.

What Each Part of Medicare Covers

Medicare is divided into four parts. Knowing what each one covers is the foundation of making smart choices.

Medicare Part A: Hospital Insurance

Part A generally covers:

• Inpatient hospital stays

• Skilled nursing facility care

• Hospice care

• Some home health care

In 2025, most people don’t pay a premium for Part A if they have at least 40 quarters (10 years) of Medicare-covered employment. However, there is an inpatient deductible of $1,676 per benefit period.

Medicare Part B: Medical Insurance

Part B helps cover:

• Doctor visits

• Outpatient services

• Preventive care

• Durable medical equipment

• Mental health services

In 2025, the standard Part B premium is $185 per month, with an annual deductible of $257. After the deductible, you typically pay 20% of the Medicare-approved amount for covered services.

Medicare Part C: Medicare Advantage

This is an alternative to Original Medicare, offered by private insurance companies approved by Medicare. It includes the benefits of Parts A and B and often Part D.

In 2025, many Medicare Advantage plans offer extra benefits like dental, vision, and hearing services. However, these plans can have different networks, referral requirements, and out-of-pocket limits. It’s important to compare carefully, as benefits vary.

Medicare Part D: Prescription Drug Coverage

Part D is optional and helps cover the cost of prescription medications. It is offered through private insurers approved by Medicare.

For 2025:

• The standard deductible is $590.

• Out-of-pocket spending is now capped at $2,000 for the year.

After reaching the cap, your plan pays 100% of covered drug costs for the rest of the year.

Late Enrollment Penalties Can Last a Lifetime

The consequences of missing your enrollment period go beyond inconvenience.

• Part B penalty: 10% added to your premium for every 12 months you delay enrollment without qualifying coverage.

• Part D penalty: 1% of the national base premium multiplied by the number of full uncovered months you were eligible but didn’t enroll.

These penalties are permanent.

When to Consider Delaying Enrollment

You can delay Medicare without penalty if:

• You (or your spouse) are still working and covered under an employer plan.

• The employer has 20 or more employees.

In this case, you can enroll later during a Special Enrollment Period. Be sure to get proof of creditable coverage when you leave the plan to avoid delays or penalties.

Coverage Doesn’t Happen Automatically for Everyone

If you’re already receiving Social Security benefits when you turn 65, you’ll be automatically enrolled in Parts A and B. If not, you must actively sign up during your IEP.

You should apply through the Social Security Administration (SSA). The process can be done online, over the phone, or in person.

How Medicare and Employer Coverage Work Together

Medicare coordination with your employer health plan depends on the size of your employer:

• 20+ employees: Your employer plan pays first, Medicare is secondary.

• Fewer than 20 employees: Medicare pays first, and your employer plan may not cover costs if you aren’t enrolled in Medicare.

Always confirm how your current plan coordinates with Medicare to avoid unexpected expenses.

Why You Should Compare Part D Plans Annually

Even if you already have a Part D plan, don’t assume it will stay the same. Formularies, copayments, and pharmacy networks can change each year.

The Annual Enrollment Period (AEP), from October 15 to December 7, is your chance to:

• Switch Part D plans

• Join a plan if you didn’t before

• Drop coverage if no longer needed (though penalties may apply)

Medicare Advantage Open Enrollment Period

From January 1 to March 31 each year, if you’re enrolled in a Medicare Advantage plan, you can:

• Switch to another Medicare Advantage plan

• Return to Original Medicare and join a Part D plan

This window only allows one change, and you must already be enrolled in a Medicare Advantage plan to use it.

What About Medicare and HSAs?

Once you enroll in any part of Medicare, you can no longer contribute to a Health Savings Account (HSA). If you’re working past age 65 and have an HSA, consider delaying Medicare enrollment (if eligible) to continue contributing.

However, you can still use existing HSA funds to pay for qualified medical expenses, including Medicare premiums (except Medigap).

Choosing Between Original Medicare and Medicare Advantage

The choice between these two paths isn’t simple. Here’s what you need to evaluate:

Original Medicare

• National coverage with any provider who accepts Medicare

• Separate Part D and Medigap policies may be needed

• No out-of-pocket maximum

Medicare Advantage

• All-in-one coverage, often with extra benefits

• Limited to provider networks, may require referrals

• Has an out-of-pocket maximum (up to $9,350 for in-network care in 2025)

Your choice should depend on your health needs, travel habits, and budget.

Medigap Policies Aren’t Part of Medicare

Medigap (Medicare Supplement Insurance) is optional and sold by private companies. It helps cover costs like deductibles, coinsurance, and copayments in Original Medicare.

You can buy a Medigap policy during your Medigap Open Enrollment Period, which lasts 6 months starting the month you are 65 or older and enrolled in Part B. After this period, you may be denied coverage or charged more due to pre-existing conditions.

Medigap policies don’t work with Medicare Advantage.

Stay Organized: What You Need to Track

To stay on top of Medicare in 2025, keep an eye on the following dates:

• Initial Enrollment Period: 7 months around your 65th birthday

• General Enrollment Period: Jan 1 – Mar 31

• Medicare Advantage Open Enrollment: Jan 1 – Mar 31

• Annual Enrollment Period: Oct 15 – Dec 7

Keep a folder (digital or paper) with your:

• Medicare card and correspondence

• Employer coverage proof (if delaying Medicare)

• List of medications and providers

• Notices of plan changes (ANOC letters)

Don’t Let the Enrollment Window Shut You Out

Failing to understand the timing and structure of Medicare can cost you more than just money—it can delay care, create coverage gaps, and saddle you with lifetime penalties. With clear enrollment windows and specific costs in 2025, there’s no excuse to wait.

Make sure you understand when you’re eligible, how the parts of Medicare fit together, and what options make the most sense for your situation. If you’re unsure where to begin, reach out for guidance.

Speak with a licensed agent listed on this website to ensure your Medicare coverage meets your actual needs before time runs out.​​​​​​​