Medicare Is Not One Plan
Most people turning 65 assume Medicare is a single program — you sign up, you’re covered. The reality is more nuanced, and understanding the structure is what separates people who make confident enrollment decisions from those who end up confused, underinsured, or paying penalties they didn’t see coming.
Medicare is divided into four parts. Each covers something different. Each has its own premiums, deductibles, and enrollment rules. And the combination you choose will define what you pay and what gets covered for years to come.
Here’s what each part actually does — in plain English.
Medicare Part A
Hospital Insurance
Part A is what most people think of when they hear “Medicare.” It covers care you receive as an inpatient — meaning you’ve been formally admitted to a hospital, not just treated in the emergency room and sent home.
What Part A covers:
What it does not cover: Long-term custodial care, private nursing home care, or care received while on “observation status.” Being placed on observation rather than formally admitted means Part A may not apply — and this surprises many people after the fact.
Premium
$0 for most people*
Inpatient Deductible
$1,676 per benefit period
Days 1–60 Coinsurance
$0 after deductible
*Most people qualify for premium-free Part A after paying Medicare taxes for at least 10 years (40 quarters).
Medicare Part B
Medical Insurance
Part B covers the medical care you receive outside of a hospital stay — doctor visits, outpatient procedures, lab work, imaging, and preventive services. If Part A is what covers you when you’re admitted, Part B covers almost everything else.
What Part B covers:
What it does not cover: Routine dental, vision, hearing, or prescription drugs. These are significant gaps that many people don’t anticipate when they first enroll.
Standard Premium
$185/month (2025)
Annual Deductible
$257 (2025)
Coinsurance
20% of approved costs
The 20% Problem Nobody Talks About
Original Medicare has no out-of-pocket maximum. That 20% coinsurance under Part B has no ceiling. For someone with ongoing dialysis, cancer treatment, or another serious condition, that exposure can reach tens of thousands of dollars a year — indefinitely, year after year.
This is the core reason Medicare Supplement plans exist. Understanding this gap is essential before you choose between Advantage and a Supplement.
Medicare Part C
Medicare Advantage
Part C is not a separate layer of coverage — it’s an alternative way to receive your Part A and Part B benefits. Instead of getting coverage directly through the federal government, you get it through a private insurance company that contracts with Medicare.
These plans are called Medicare Advantage plans. They must cover everything Parts A and B cover, and most also include Part D drug coverage, plus extras like dental, vision, and hearing benefits.
What Part C typically includes:
The trade-off: Medicare Advantage plans use provider networks. You’ll typically need referrals to see specialists, and care outside the network may cost significantly more — or not be covered at all. Prior authorizations are common for major procedures.
Premium
Often $0 (plus Part B premium)
Out-of-Pocket Max
Up to $9,350/year in-network (2025)
Medicare Part D
Prescription Drug Coverage
Part D is prescription drug coverage. It’s offered through private insurance companies approved by Medicare and is entirely separate from Parts A and B. If you have Original Medicare without a Medicare Advantage plan, you need to enroll in a standalone Part D plan to have drug coverage.
Every Part D plan has a formulary — a list of covered drugs organized into tiers. Your cost depends on which tier your medication falls into, and not every drug is on every plan’s formulary.
What Part D covers:
The late enrollment penalty: If you don’t enroll in Part D when you’re first eligible — and you don’t have other creditable drug coverage — you’ll pay a permanent penalty added to your premium for every month you went without. This penalty doesn’t go away.
Average Premium
~$40–$60/month
Annual Out-of-Pocket Cap
$2,000 (2025)
The Four Parts at a Glance
Once you understand what each part does, everything else about Medicare starts to make more sense — including why the plan decisions you make at 65 carry such long-term weight.
| Part | Nickname | What It Covers | Who Provides It |
|---|---|---|---|
| Part A | Hospital Insurance | Inpatient hospital, skilled nursing, hospice | Federal government |
| Part B | Medical Insurance | Doctor visits, outpatient care, preventive services | Federal government |
| Part C | Medicare Advantage | Parts A + B + extras (usually includes Part D) | Private insurer |
| Part D | Drug Coverage | Prescription medications | Private insurer |
What None of the Parts Cover
Understanding the parts also means understanding what they don’t cover by default. These are the most common surprises for new Medicare enrollees — and knowing them in advance lets you plan for them rather than discover them at the worst possible moment.
Gaps in Original Medicare (Parts A & B)
- Routine dental care — cleanings, fillings, crowns, dentures
- Routine vision care — annual eye exams, eyeglasses, contact lenses
- Hearing aids and routine hearing exams
- Long-term custodial care — help with daily activities in a nursing home or at home
- Cosmetic procedures
- Most care received outside the United States
Medicare Advantage plans (Part C) often include some dental, vision, and hearing benefits — but the extent of that coverage varies significantly from plan to plan, and it can change year to year when a plan updates its benefits.
How the Parts Work Together
When you enroll in Medicare you’re essentially choosing between two paths. Understanding the parts is how you understand the difference.
Path 1: Original Medicare
Parts A + B from the federal government, a standalone Medigap Supplement to cover the gaps, and a separate Part D plan for prescriptions. More predictable costs, broader provider access, no networks.
Path 2: Medicare Advantage
Part C bundles A, B, and usually D into one private plan. Often $0 premium with extra benefits like dental and vision. Trade-off is provider networks, referrals, and prior authorizations.
The Decision That Follows You
The path you choose at 65 affects your ability to switch later. Once your initial Medigap window closes, moving to a Supplement requires medical underwriting — and approval is not guaranteed.
Know Your Options Before You Enroll
The parts are just the beginning. The real question is which combination fits your life — your health, your doctors, your prescriptions, and your budget. What matters most isn’t memorizing every rule. It’s understanding enough to ask the right questions before you enroll.
The Best Time to Understand All Your Options Is Before You Decide
Once your initial Medigap enrollment window closes at 65, your options narrow. Plans that seem like the obvious choice when you’re healthy can look very different after a serious diagnosis. The decisions you make now follow you for years.
As an independent advisor, I don’t work for any insurance company. I review plans from most major carriers and show you every option available in your area — so you can make an informed decision with full clarity, not just the information one carrier wants you to have.
There’s no cost to you for this guidance. My service is free — paid by the carrier when you enroll, at no extra cost to you regardless of which plan you choose.