Key Takeaways

• Medicare Part B is critical for covering outpatient services, but enrolling at the wrong time can lead to late penalties and coverage gaps.

• Understanding the coordination between Part B, other Medicare parts, and employer or retiree coverage is essential to avoid unnecessary costs.

Why Medicare Part B Matters More Than You Think

If you’re eligible for Medicare in 2025, you’ve likely heard that Part B covers your doctor visits. But what you may not realize is that Part B is more than just a nice-to-have—it’s foundational for comprehensive Medicare coverage. Without it, your access to outpatient care, preventive services, and even supplemental coverage options can be severely limited.

Part B is the part of Medicare that covers:

• Doctor visits

• Preventive screenings (like mammograms and colonoscopies)

• Outpatient procedures

• Durable medical equipment

• Mental health services

• Lab tests and X-rays

However, enrolling in Part B is not always automatic—and it’s not free. You pay a monthly premium, and the costs can increase if you delay enrollment.

When You Must Enroll in Part B

Timing is everything with Part B. If you’re not automatically enrolled (such as when you’re already receiving Social Security benefits before age 65), then it’s your responsibility to sign up during the right enrollment window.

Initial Enrollment Period (IEP)

This is a 7-month window:

• Starts 3 months before the month you turn 65

• Includes the month of your 65th birthday

• Ends 3 months after your birthday month

If you enroll in the first three months, your Part B coverage starts the month you turn 65. If you enroll later in the IEP, your coverage could be delayed.

Special Enrollment Period (SEP)

If you’re still working and have employer coverage (or are covered by a spouse’s active employment plan), you can delay Part B without penalty. Once that coverage ends, you get an 8-month SEP to enroll.

General Enrollment Period (GEP)

If you miss your IEP and don’t qualify for a SEP, you’ll have to wait for the General Enrollment Period, which runs from January 1 to March 31. Coverage starts July 1—and you may face permanent late penalties.

The Part B Late Enrollment Penalty

One of the most misunderstood aspects of Medicare Part B is the penalty. If you don’t enroll during your IEP or SEP and don’t have creditable coverage, you’ll pay a late enrollment penalty.

Here’s how it works in 2025:

• The penalty adds 10% to your monthly premium for each full 12-month period you were eligible but not enrolled.

• This penalty is permanent—you’ll pay it for as long as you have Part B.

This can add up quickly. A two-year delay could mean paying 20% more each month—for life.

What Part B Doesn’t Cover

While Part B fills a crucial gap in your healthcare coverage, it doesn’t pay for everything. Knowing what’s not included is just as important as knowing what is.

Part B does not cover:

• Hospital stays (covered by Part A)

• Most dental, vision, and hearing care

• Long-term custodial care

• Prescription drugs (covered under Part D)

To get full protection, you’ll likely need additional coverage beyond Part B, such as a Part D drug plan or a Medicare Supplement policy—but those often require active Part B enrollment.

Coordinating Part B with Other Coverage

If you’re still working at 65—or covered by a spouse’s employer plan—you may not need to enroll in Part B right away. But coordination rules matter.

Employer Size Matters

• If your (or your spouse’s) employer has 20 or more employees, the employer coverage pays first, and you can delay Part B without penalty.

• If the employer has fewer than 20 employees, Medicare is primary. You should enroll in Part B to avoid gaps.

Retiree Coverage or COBRA

Neither of these count as active employer coverage under Medicare’s rules. So if you delay Part B based on COBRA or retiree insurance, you will face penalties and gaps.

What You Pay Under Part B in 2025

In 2025, the standard monthly premium for Part B is $185. But if your income is higher, you may pay more due to the Income-Related Monthly Adjustment Amount (IRMAA).

Other Part B Costs

• Annual deductible: $257

• Coinsurance: After meeting your deductible, you typically pay 20% of the Medicare-approved amount for services.

There is no out-of-pocket maximum under Original Medicare, which is why many people consider adding supplemental coverage.

Why You May Still Need Part B—Even With Other Insurance

Many retirees assume they don’t need Part B if they have other coverage, like a retiree plan or military benefits. But most of those plans require Part B enrollment for full coordination.

• FEHB (Federal Employees Health Benefits): You’re not required to enroll in Part B, but many plans waive deductibles and coinsurance if you do.

• TRICARE for Life: Requires enrollment in Part B.

• Veterans Affairs (VA): You can use both, but VA care is limited to VA facilities. Medicare gives you access elsewhere.

Skipping Part B could mean paying full cost out-of-pocket if you get care outside your other plan’s network.

Common Part B Enrollment Mistakes

It’s surprisingly easy to get tripped up by Medicare Part B rules. Here are some common pitfalls you’ll want to avoid:

• Assuming you’re automatically enrolled when you’re not

• Delaying Part B based on COBRA or retiree insurance

• Missing the 8-month SEP window after losing employer coverage

• Failing to understand the employer size rule

• Waiting for the GEP and ending up with a coverage gap

Mistakes like these can lead to higher premiums and limited access to care.

How to Apply for Medicare Part B

If you’re already receiving Social Security or Railroad Retirement Board benefits, you’ll be automatically enrolled in Parts A and B starting the month you turn 65. You’ll receive your Medicare card about 3 months before your birthday.

If you’re not automatically enrolled, here’s how to sign up:

• Apply online at the Social Security website

• Call Social Security at 1-800-772-1213

• Visit your local Social Security office

If you’re applying during a Special Enrollment Period after employer coverage ends, your employer must complete Form CMS-L564 to confirm you had creditable coverage.

What If You Want to Drop Part B?

While most people benefit from having Part B, some consider dropping it due to the monthly premium. But you should be extremely cautious.

Dropping Part B means:

• You lose coverage for all outpatient services

• You can’t buy a Medicare Supplement plan

• You may not qualify for re-enrollment until the next GEP, with penalties

If you’re considering dropping Part B for any reason, talk with a licensed agent listed on this website first.

A Final Word About Getting the Most Out of Part B

Medicare Part B is a key piece of your healthcare puzzle. Without it, you’re exposed to major risks—financial and medical. The timing of your enrollment matters, your coverage options depend on it, and the cost of making a mistake can last for years.

Before you delay or opt out, consider how Part B connects to everything else. It’s not just about doctor visits—it’s the gateway to a more complete Medicare plan.

If you’re unsure how Part B fits into your personal situation, get in touch with a licensed agent listed on this website. They can help you understand your enrollment options and avoid costly mistakes.