Key Takeaways

• Many commonly held assumptions about Medicare coverage and costs are incorrect in 2025 and can lead to costly surprises if you’re not paying attention.

• Understanding how enrollment windows, plan rules, and coordination with other coverage actually work is critical to avoiding penalties and gaps.

Not Every Enrollment Period Works the Way You Assume

One of the most common misunderstandings about Medicare is how enrollment periods actually function. Many people think they can sign up anytime or assume they’ll be reminded when it’s time. That’s not how Medicare works.

Initial Enrollment Period (IEP) Isn’t Always Flexible

Your Initial Enrollment Period lasts for seven months: it starts three months before the month you turn 65, includes your birthday month, and ends three months after. If you miss this window and don’t qualify for a Special Enrollment Period, you may be stuck waiting until the General Enrollment Period.

General Enrollment Period Comes With Penalties

If you miss your IEP, you’ll have to wait until the General Enrollment Period (January 1 to March 31), and your coverage won’t begin until July 1. You may also face late enrollment penalties that stick with you for life—especially for Part B and Part D.

Special Enrollment Periods Are Not Guaranteed

Many people assume they’ll qualify for a Special Enrollment Period (SEP) if they miss the initial window. But SEPs only apply under specific circumstances—such as losing employer coverage or moving out of your plan’s service area. Retirement without employer-sponsored coverage does not automatically grant you a SEP.

Delaying Part B Isn’t Always a Smart Cost-Saver

It might seem financially savvy to delay Part B enrollment to avoid paying monthly premiums if you’re still working. But that strategy can backfire quickly.

• If your employer coverage isn’t considered “creditable,” you may face lifetime penalties when you do enroll.

• Coordination of benefits between Medicare and employer plans isn’t automatic. You may find that Medicare becomes your primary payer sooner than you expect.

In 2025, the standard Part B premium is $185 per month, and delaying this to save money—if done incorrectly—can result in a permanent penalty that adds 10% for each 12-month period you went without coverage.

Medicare Advantage Isn’t Automatically Better Than Original Medicare

There’s a common belief that Medicare Advantage (Part C) is just Medicare with extra perks. That’s not how it works.

While some Medicare Advantage plans do offer additional benefits, they also come with:

• Restricted provider networks

• Prior authorization requirements

• Limited regional availability

You may also face higher out-of-pocket costs for certain services. Original Medicare, by contrast, allows broader provider access and doesn’t require referrals.

You Can’t Enroll in Medicare Part D Whenever You Want

Prescription drug coverage under Part D has strict enrollment periods. If you don’t sign up when first eligible, and you don’t have other creditable coverage, you’ll pay a late enrollment penalty that increases with every month you delay.

Even though Medicare Part D no longer has a coverage gap (as of 2025), your choice of plan and when you enroll still affects your costs and access. You must wait for Medicare’s Annual Enrollment Period (October 15 to December 7) unless you qualify for a Special Enrollment Period.

Dropping Part D or Part B Later Can Be Risky

Some people drop Part D or Part B coverage later on thinking they won’t need it anymore. That’s a mistake that could lock you out of affordable coverage.

• Dropping Part B means you may have to wait until the next General Enrollment Period to get back in, and penalties will apply.

• Dropping Part D and then re-enrolling later will restart penalty calculations unless you had creditable drug coverage in the meantime.

You Don’t Automatically Get All the Help You May Qualify For

Medicare beneficiaries with limited income may qualify for programs like Medicaid, Extra Help, or a Medicare Savings Program. But none of these are automatic.

You must apply for them through your state or Social Security. Missing out means you could be paying hundreds more each month than necessary.

In 2025, the Extra Help program now offers full benefits to more individuals, but income and resource limits still apply. Don’t assume you’re automatically enrolled—you aren’t.

Not All Services Are Covered Just Because They’re Medically Necessary

Another misunderstood rule: Medicare doesn’t cover every medically necessary service.

• Dental, vision, and hearing care are not included under Original Medicare.

• Long-term custodial care is not covered.

• Routine foot care, most cosmetic surgeries, and personal care assistance are typically excluded.

Some Medicare Advantage plans include limited coverage for these, but they are not standard benefits. Always read your plan’s Evidence of Coverage.

Coordination With Employer Coverage Doesn’t Always Work the Way You Expect

If you’re still working past 65, the interaction between Medicare and your employer health plan depends on the size of the employer.

• If the employer has fewer than 20 employees, Medicare is primary.

• If the employer has 20 or more employees, your employer plan is usually primary.

Assuming your employer plan will always pay first could lead to denied claims or uncovered services. You should speak with your employer’s benefits administrator and compare both options.

COBRA Is Not a Substitute for Medicare

If you retire and elect COBRA instead of signing up for Medicare, you could face major consequences.

COBRA coverage is not considered creditable for Medicare Part B. If you delay Part B thinking COBRA will keep you covered, you’ll face late enrollment penalties and coverage delays.

In 2025, this continues to be one of the costliest misunderstandings people make.

You Don’t Automatically Keep the Same Plan Year After Year

Even if you’re satisfied with your current Medicare Advantage or Part D plan, that plan can change from year to year. Benefits, premiums, provider networks, and drug formularies can all shift.

Every fall, you should review the Annual Notice of Change mailed to you. If you ignore it, you might find that your doctor is no longer in-network or that your prescription drug isn’t covered anymore.

Medicare Doesn’t Cover Your Spouse

Medicare is individual health insurance. There are no joint plans.

Even if you and your spouse are both turning 65, you must each enroll separately. Also, one spouse’s enrollment doesn’t qualify the other for any benefits or discounts.

In 2025, there are no family plans under Medicare—coverage and costs apply per individual.

Medicare Doesn’t Replace All Health Insurance Needs

Many people mistakenly think that once they enroll in Medicare, they’re fully covered. But Medicare has gaps:

• No out-of-pocket maximum under Original Medicare

• Deductibles and coinsurance for hospital and outpatient care

• No standard coverage for foreign travel emergencies

To fill these gaps, many people consider Medigap plans or opt for a Medicare Advantage plan that offers a cap on out-of-pocket costs. But again, these are separate enrollments, and rules apply.

Understanding the Real Rules Empowers You to Make the Right Choices

Medicare can feel deceptively simple from a distance—but the rules you think are obvious often aren’t accurate once you’re enrolled. By staying informed and taking time to review each part of Medicare, you protect yourself from late penalties, denied services, and expensive gaps in coverage.

The most effective step you can take now? Get guidance. If you’re unsure how these rules apply to you or if your situation has unique factors, speak to a licensed agent listed on this website. They can help you avoid making assumptions that cost you later.