Medicare — Your Map to the Basics

Paying for Health Care in Retirement | For New and Current Medicare Enrollees

Medicare is loaded with letters … as if you have been dropped into an alien environment where everyone speaks A, B, C, D, G, K, L, N. The rules are complicated, the costs aren’t always obvious, and last year’s rules may have changed this year. On top of having a wide variety of options and letters, a decision made at the wrong time can follow you for years.

You need a map to navigate Medicare –the ABCs.

The good news: You don’t need to become a Medicare expert. You do need to understand the basic choices, what they cover (or don’t), the important deadlines, and the gaps that can leave you paying out of pocket.

This guide is for people approaching 65 and for current Medicare enrollees who want a quick basic refresher (i.e., scan the Table of Contents below and skip ahead to whatever you’re still unsure about). Think of it as your map: this article explains the big picture and the decisions that matter the most, while the companion articles in this series take you deeper into individual parts of Medicare.

This guide won’t tell you which path is best: (1) the federal government-run health insurance program, Original Medicare or (2) the privately-run program, Medicare Advantage Plan.  Nor will it tell you whether a particular Medigap policy (i.e., Plan G or Plan N) sold by private companies to cover Medicare Part A and Part B cost-sharing requirements fill the gaps in coverage is the better fit. Those choices involve trade-offs, and the right choice depends on factors that are vital to you (such as your health needs, budget, doctors, prescription drugs, travel plans, and how much you value predictable costs versus flexibility). What plan was best for you this year may not be best for next year.

Admittedly, it is not the most fun way to spend a weekend. But the goal here is simpler: to help you understand the choices well enough to ask the right questions as you age. It can make huge differences in your future.

Still working at 65? If you’re still working, or you’re covered through a spouse’s current employer, don’t automatically sign up for Medicare just because you’re turning 65. But don’t automatically delay it, either.  It is important to be aware of the size of your employer, the type of coverage you have, and whether you put money into a Health Savings Account (HSA). All of these factors can affect what you should do and when. Before your 65^th birthday, research your options ahead of your retirement. Ask your employer’s benefits department how the employer plan works with Medicare and whether enrolling in Medicare would affect HSA contributions.

Medicare Cost plans: Availability is limited to geographic areas where there are few or no Medicare Advantage plans.  Many are being phased out in favor of Medicare Advantage plans. One very attractive plus to the cost plan is the flexibility of receiving care both in and out of the plan’s network.

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Something to Note:

You don’t have to sort this out alone.

(1) Medicare.gov provides official information about Medicare coverage, costs, enrollment, and plan choices. Use the Plan Finder tool to view the plans available in your ZIP code and call 1-800-MEDICARE (1-800-633-4227).

(2) State Health Insurance Assistance Program (SHIP) is an independent government program with trained counselors in every state. It offers free, unbiased, one-on-one Medicare counseling. SHIP counselors do not sell Medicare plans.

(3) A licensed Medicare broker can help you compare plans at no cost to you. Brokers are paid by the insurance companies.

TIP: Ask which specific insurers the broker represents, as they may not cover every company in your area.

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What’s Covered in This Series: 

• • • • This Article: Medicare — Your Map to the Basics
      • Article 2: Sleuthing Through the Alphabet World of Medicare: What Part A and Part B Actually Cover
      • Article 3: Medicare Part D in 2027: Besides Giving You a Headache and Nightmares
      • Article 4: Filling the Gaps in Original Medicare: Medicare Supplement Insurance (Medigap)
      • Article 5: Medigap Plans Compared: G, N, K, and L
      • Article 6: How to Shop for a Medicare Advantage Plan: A Practical Guide to Comparing Plans
      • Article 7: Help Paying for Medicare
      • Article 8: Appealing a Medicare Decision: Denials, Coverage Decisions, and IRMAA

What’s Covered in This Article:

1. The Big Picture: Think in Parts
2. If You Choose Original Medicare, Know the Two Major Add-ons
3. Original Medicare v. Medicare Advantage: The Big Picture
4. Are Medicare Advantage Plans Really an “Advantage”?
5. Enrollment Timing: The Deadlines That Matter Most
6. Why Medicare’s Gaps Matter
7. When Can You Change Medicare Coverage?
8. A Special Caution About Medigap When Switching?
9. The Bottom Line

The Big Picture: Think in Parts

Many believe that the Medicare payroll taxes taken from wages will fully fund future health care once they turned 65.  Not quite so. Others see Medicare as confusing: why is a program as crucial as Medicare dominated by letters of the alphabet?

A useful way to think about Medicare is breaking it down into three layers:

Layer 1:  Original Medicare.

Consists of Part A—hospital insurance and Part B—outpatient medical insurance.  Together, Parts A and B cover a wide range of medically necessary health care and certain preventive services.

Layer 2:  How you receive your Medicare benefits.

Once you are eligible for Medicare, you generally choose between two ways of receiving your health care:

(1) Original Medicare (Part A and Part B):  Administered by the federal government without the involvement of private insurers, or

(2) Medicare Advantage (Part C): Offered by private insurance companies approved and regulated by the federal agency that oversees Medicare.

Layer 3:  Additional coverage.

Depending on the path you choose, you may also have other coverage:

• Part D: Prescription drug coverage. 
• Medigap: Medicare Supplement Insurance, which can help pay deductibles and certain other costs that Original Medicare doesn’t cover 
• Financial assistance programs: for people who qualify based on income and other circumstances.

If You Choose Original Medicare, Know the Two Major Add-ons

If you go with Original Medicare, two types of additional coverage are particularly important to understand:

• Plan D prescription drug coverage: Purchased separately through a private insurance plan at a cost determined by the insurer, subject to federal approval. Part D coverage is optional. You may be able to delay enrollment in Part D if you have other creditable prescription drug coverage. HOWEVER, going without Part D or other creditable coverage for too long can trigger a permanent late-enrollment penalty.
• Medigap (also called Medicare Supplement Insurance): Private insurance that helps pay health care costs that Original Medicare doesn’t cover (such as deductibles and co-insurance). Medigap policies are automatically renewed each year. An insurer cannot cancel your policy as long as you pay the premium, though your premium can rise over time.

Original Medicare v. Medicare Advantage: The Big Picture

	Original Medicare	Medicare Advantage
Who runs it?	Federal government	Private, Medicare-approved insurer
Part A & B coverage	Directly through Medicare; Part B has a monthly premium and an annual deductible	Through your private plan
Doctor choice	Generally, any provider who accepts Medicare	Usually restricted to a plan network
Drug coverage Part D	Usually purchased separately	Usually included
Medigap pairing	Can be paired with Original Medicare	Cannot be paired
Out-of-pocket limit	No annual limit on out-of-pocket costs	Has an annual spending limit for covered Part A/B services
Extra plan rules & approvals	Generally fewer restrictions	May include networks, referrals, and prior authorization requirements

There’s no universal winner. The details vary by plan and by individual circumstances. The better question is: which arrangement fits your health, your doctors, and your budget?  For a deeper look at Advantage plans specifically — including how to shop for one — see our [companion article].) For how Medigap fills Original Medicare’s gaps, see our [companion reference guide].  

Medicare Advantage Plans Really an “Advantage”?

According to KFF, more than half of all people eligible for Medicare Part A and B are enrolled in a Medicare Advantage (MA) plan, signaling that many find the plans to be an attractive choice. Medicare Advantage plans offer one-stop shopping, often bundling drug coverage, extras like dental, vision and flex debit cards, plus a yearly cap on your out-of-pocket costs.

But not surprisingly, there are tradeoffs. You will usually need to use the plan’s network of doctors or pay more to go outside it. Plans also frequently require prior approval or referrals before certain care is authorized. Original Medicare, by contrast, lets you see any doctor or hospital in the country that accepts Medicare, with far fewer approval hurdles, but leaves you vulnerable to unlimited out-of-pocket cap unless you purchase a Medigap policy.

Another hiccup you might want to take into account: what is your tolerance for a Medicare Advantage plan change in its supplemental benefits from one year to the next? Insurers reset their premiums, copays, and supplemental benefits to maintain profitability every year. This means you might not get exactly the same benefits (more expensive or less generous), making them less valuable.

What your MA plan is changing, and how, is detailed in an ANOC sent in September. Don’t leave it unopened!

Enrollment Timing: The Deadlines That Matter Most

Probably the single biggest Medicare mistake people make is missing an enrollment window. This is an important deadline to keep on your radar. Depending on your circumstances, missing the right window can leave you with a dangerous gap in coverage, a late-enrollment penalty, or both.

Your first window: the Initial Enrollment Period. A 7-month window starting 3 months before the month you turn 65, including your birthday month, and ending 3 months after you turn 65.  Signing up early in the window helps avoid coverage delays.

Missed your first window?  The General Enrollment Period. Runs January 1 to March 31 each year if you missed your initial window. Coverage starts the month after you sign up, but late enrollment penalties may also apply.

The Part B penalty. If you don’t sign up for Part B when you’re first eligible, and you don’t have qualifying coverage from a current employer, your premium increases by a standard 10% for each full 12-month period you went without it. In most cases, you will pay that higher premium for as long as you have Part B.

The Medigap window you get only once:  Your 6-month Medigap Open Enrollment Period starts the month you’re 65 or older and enrolled in Part B. During that time, insurers must sell you any Medigap policy they offer, regardless of your health.  After it ends, insurers in most states can ask health questions, charge you more or turn you down entirely.

What about a younger spouse? Medicare is individual coverage, not family coverage. A spouse or dependent does not receive Medicare simply because you do. If you retire and your younger spouse loses employer-sponsored family coverage, that spouse will need alternative coverage (such as an ACA Marketplace plan or COBRA) if they lose employer-sponsored family overage.

Why Medicare’s Gaps Matter

One of the most important facts to understand about Original Medicare is that there is no annual out-of-pocket maximum for covered Part A and Part B services.

That doesn’t mean you will face enormous medical bills. Or financial ruin.  It simply means Original Medicare itself does not put a yearly ceiling on your share of covered Part A and B costs.  That is why many people who choose Original Medicare buy a Medigap policy. Medicare Advantage plans, by contrast, protect you with an annual out-of-pocket spending cap, though the amount varies by plan.

When Can You Change Medicare Coverage?

Once enrolled, you may have several opportunities to change your coverage.  Which opportunities apply to you depends on what coverage you have and what you are trying to change.

1. October 15 – December 7: Annual Enrollment Period (AEP). Make changes to Medicare Advantage and Part D coverage for the following year or switch between Original Medicare and privately-run Medicare Advantage plans in your area. Changes generally take effect January 1. If you miss this window — and do not qualify for another one — you’ll wait until next year’s AEP.
2. January 1 – March 31: Medicare Advantage Open Enrollment. If you’re already in a Medicare Advantage plan, you can switch to: (1) another Medicare Advantage plan or (2) return to Original Medicare.
3. Special Enrollment Periods. Certain life events — like moving or losing qualifying employer coverage — can open a window outside the standard calendar.

A Special Caution About Medigap When Switching

Changing your Medicare coverage and buying a Medigap policy are two entirely separate things. You may be able to switch from Medicare Advantage back to Original Medicare during an enrollment period, but that does not necessarily mean a Medigap insurer must sell you a policy without medical underwriting. Outside your one-time Medigap open enrollment period, insurers in most states can use your health history to set your price or deny you coverage. Check your Medigap options before switching away from an Advantage plan.

The Bottom Line

Medicare doesn’t have to become your second career. But you do need the basic map before you make decisions, because the choices you make when you first enroll—and the coverage you choose afterward– can affect your costs, your doctors and your options for years.

Start with four questions:

1. When do I need to enroll?  Your answer may depend on your age, whether you’re working, your employer’s coverage, and other circumstances.
2. Do I want to enroll?  After your employer-provided coverage ends, the answer is almost always yes. You might not want to enroll if you live overseas (as Medicare does not cover healthcare delivered outside the US), but if you plan to return, it may be advantageous to enroll when you turn 65.  If you wait until you return, you’ll need to pay the late enrollment penalty for the rest of your life.
3. Do I want Original Medicare or Medicare Advantage? Neither is automatically right for everyone.  Look at the trade-offs involving doctors, networks, costs, coverage and convenience.
4. If I choose Original Medicare, how will I handle the gaps? You will want to understand Part D and Medigap—and whether you have other coverage that fills those needs.

From there, the decisions become more manageable. If you’re approaching 65, start early. If you’re already enrolled, use the Annual Enrollment Period each fall to review your coverage rather than letting it renew on autopilot. And don’t be afraid to ask questions. You want to get it right. Medicare is complicated enough without deciding under pressure.

Continue the series: 

[Part A and Part B] · [Part D] · [Medigap] ·  [Medigap Plans: G, N, K, and L] ·  [Medicare Advantage Plans] · [Financial Assistance] · [Appeals]