Key Takeaways

• Medicare enrollment has fixed windows that you must follow, or you could face lifelong penalties.

• Choosing between Original Medicare and Medicare Advantage is more than a financial decision—it impacts access, flexibility, and coverage.

The Importance of Timing: When You Can Enroll

You don’t get to choose your own timeline when it comes to Medicare. There are specific enrollment periods that govern when you can sign up for coverage—and if you miss them, you may face penalties or coverage delays.

Initial Enrollment Period (IEP)

This is the seven-month window around your 65th birthday. It begins three months before your birth month, includes your birth month, and ends three months afterward. This is your first opportunity to enroll in Medicare Parts A and B.

• Enrolling during the first three months allows your coverage to start on the first day of your birthday month.

• If you enroll during your birth month or the final three months, your coverage may be delayed.

General Enrollment Period (GEP)

If you missed your IEP and didn’t qualify for a Special Enrollment Period, you can enroll during the General Enrollment Period, which runs from January 1 to March 31 each year. However, coverage begins July 1, and you may face a late enrollment penalty.

Special Enrollment Periods (SEPs)

These are triggered by specific events like retiring after 65 or losing employer health coverage. The SEP usually lasts eight months from the date your job-based coverage ends. Not all life events qualify—so you must check your eligibility carefully.

Medicare Advantage and Part D Open Enrollment

From October 15 to December 7 each year, you can:

• Switch from Original Medicare to a Medicare Advantage plan or vice versa

• Join, drop, or change a Part D prescription drug plan

Changes made during this window take effect on January 1 of the following year.

The First Big Choice: Original Medicare or Medicare Advantage?

You’re not just enrolling in Medicare—you’re making a series of decisions. The first major choice is between Original Medicare and Medicare Advantage.

Original Medicare

Original Medicare includes:

• Part A (hospital insurance)

• Part B (medical insurance)

With Original Medicare, you can:

• Visit any doctor or hospital that accepts Medicare

• Enroll in a standalone Part D plan for prescription drugs

• Add supplemental coverage (like Medigap) to help with out-of-pocket costs

Out-of-pocket expenses can add up, including deductibles, coinsurance, and uncovered services.

Medicare Advantage (Part C)

This is an alternative offered by private plans, which must cover everything Original Medicare does but often includes extra benefits like dental, vision, or hearing. These plans usually bundle Part A, Part B, and often Part D into one.

However, choosing a Medicare Advantage plan can mean:

• Limited provider networks

• Requirement for referrals or pre-authorizations

• Changes in benefits, costs, or networks every year

The decision between the two depends on your health, preferences, and financial situation.

Understanding Part D: Prescription Drug Coverage Isn’t Automatic

If you choose Original Medicare and want drug coverage, you must enroll in a standalone Part D plan. If you choose Medicare Advantage, drug coverage is often included but not always—so double-check.

Missing your Part D Initial Enrollment Period can lead to a permanent late enrollment penalty unless you qualify for an exception. In 2025, the Part D landscape includes:

• A $2,000 annual cap on out-of-pocket drug costs

• A prescription payment plan that allows spreading costs over the year

• Coverage phases: deductible, initial coverage, and catastrophic (triggered after hitting the $2,000 limit)

Even with the new protections, some medications may still be excluded, or you might face prior authorization requirements.

What You Might Not Know About Costs

Many assume Medicare is fully paid for once you enroll, but that’s not the case. Each part of Medicare comes with its own costs, and these can vary widely depending on the choices you make.

Medicare Part A (2025)

• Usually premium-free if you or your spouse worked at least 10 years

• Hospital deductible: $1,676 per benefit period

• Coinsurance applies after 60 days of inpatient care

Medicare Part B (2025)

• Monthly premium: $185 (may be higher based on income)

• Annual deductible: $257

• After deductible, you pay 20% of Medicare-approved services

Part D (2025)

• Average premium varies

• Deductible up to $590

• Out-of-pocket costs capped at $2,000 annually

You may also face additional costs if you:

• Don’t enroll on time (late enrollment penalties)

• Choose a plan with high cost-sharing

• Have high-income-related monthly adjustment amounts (IRMAA)

Hidden Trade-Offs in Medicare Advantage Plans

While the extra benefits and all-in-one nature of Medicare Advantage plans are appealing, they come with some trade-offs you need to understand:

• Network restrictions: You may be limited to in-network providers unless you pay more out of pocket.

• Prior authorization: Many services require approval before they’re covered.

• Plan variability: Each year, your plan can change its benefits, drug formulary, and provider network.

• Less predictable costs: Copays and coinsurance can differ by service and add up over time.

These elements may not be immediately apparent when comparing plans during Open Enrollment.

When Should You Consider Medigap?

If you stick with Original Medicare, you may want to add a Medigap (Medicare Supplement Insurance) plan. These policies help pay for the costs that Original Medicare doesn’t cover.

Important Timing for Medigap

• Your Medigap Open Enrollment Period begins the month you are both 65 and enrolled in Part B

• It lasts for six months

• During this period, you can buy any Medigap plan available in your state without being denied for health conditions

After that six-month window, getting Medigap coverage could become difficult or expensive.

What Happens If You’re Still Working at 65?

Many people delay Medicare Part B or Part D if they’re still working and covered by an employer group plan.

Things to Consider:

• If the employer has fewer than 20 employees, you may need to enroll in Medicare anyway, as it becomes the primary payer

• When you retire, you have 8 months to enroll in Part B (SEP)

• COBRA coverage doesn’t count as creditable coverage for delaying Part B or Part D

Failing to understand this can lead to late enrollment penalties and gaps in coverage.

Annual Changes Make Medicare a Moving Target

Even after you enroll, your Medicare plan isn’t set in stone. You need to review your coverage every year because:

• Costs and benefits change annually

• Drug formularies and provider networks may be updated

• Your health needs or financial situation might change

The Annual Notice of Change (ANOC) letter from your plan outlines all the changes. If you don’t review it, you might miss out on better options—or end up with higher costs.

Getting Help Makes a Difference

The enrollment windows might be clear on the calendar, but the choices you make within them are anything but simple. Between coverage types, timelines, penalties, and shifting plan details, the process can quickly become overwhelming.

If you’re unsure where to begin or how to compare options, working with a licensed agent listed on this website can help you:

• Evaluate Original Medicare vs. Medicare Advantage

• Understand out-of-pocket costs

• Avoid penalties and coverage gaps

• Align your plan choice with your health and budget needs

Make the Right Moves Before the Clock Runs Out

Medicare gives you a window—but the decisions you make during that window have long-term effects. Whether you’re new to Medicare or reviewing your annual options, take the time to understand the trade-offs, costs, and rules before you act.

To make sense of your choices and avoid costly mistakes, speak with a licensed agent listed on this website who can guide you every step of the way.