Medicare, Explained Once and Properly

Medicare’s Annual Enrollment Period runs October 15 through December 7, and by the time it opens, most readers will have already made — or drifted into — the single decision that shapes nearly everything else about their healthcare for years to come. This piece exists so that decision is made on purpose.

We’re going to do this in two parts. Today: what each part of Medicare actually does, and the fork in the road between Original Medicare and Medicare Advantage — laid out as fairly as we can manage. Next Wednesday: how to read the Annual Notice of Change letter that’s about to land in your mailbox, because it quietly tells you whether the plan you have is still the plan you think you have.

The four parts, without the alphabet soup

Part A — Hospital insurance. Covers inpatient hospital stays, skilled nursing facility care after a hospital stay, hospice, and some home health care. Most people paid into this through payroll taxes for years and get it premium-free at 65.

Part B — Medical insurance. Covers doctor visits, outpatient care, preventive services, durable medical equipment, and most of what happens outside a hospital bed. The standard Part B premium is $202.90 in 2026, with 2027 projected to rise to roughly $209.50, though the official number isn’t finalized until late October or November. After your deductible, Original Medicare typically pays 80 percent of most costs — and by itself, there’s no yearly cap on the remaining 20 percent. That uncapped exposure is the fact the rest of this article is built around.

Part C — Medicare Advantage. Not a supplement to Parts A and B, but a replacement for them. Private insurers, approved by Medicare, bundle your hospital and medical coverage — usually with drug coverage and extras like dental or vision — into one plan with its own network and rules.

Part D — Prescription drug coverage. Also sold by private insurers, either standalone or bundled into a Medicare Advantage plan. For 2027, the standard deductible rises to $700 and the annual out-of-pocket cap rises to $2,400, after which your covered drug costs stop for the rest of the year.

The fork: Original Medicare or Medicare Advantage

This is the choice that shapes everything after it, and it deserves the fairest treatment we can give it.

The case for Medicare Advantage

Lower or even $0 monthly premiums beyond what you already pay for Part B. An annual out-of-pocket maximum — real protection against a catastrophic year, something Original Medicare alone doesn’t offer. Extra benefits Original Medicare doesn’t include: dental, vision, hearing, sometimes a fitness or transportation benefit. And simplicity — one card, one plan.

The case for Original Medicare plus Medigap

Near-total freedom to see any doctor or hospital in the country that accepts Medicare — no network, no referrals required. A Medicare Supplement (Medigap) policy picks up some or most of that uncapped 20 percent coinsurance, so your costs become far more predictable. And portability — if you split your year between two states, or travel extensively, Original Medicare goes with you.

Where Medicare Advantage genuinely costs you

Networks. Most Advantage plans are HMOs or PPOs with a defined list of doctors and hospitals. Prior authorization is common for procedures, imaging, and hospital stays. Referrals are frequently required to see specialists. And travel is the quiet dealbreaker for retirees: standard Medicare Advantage plans generally don’t cover care outside their service area except emergencies.

The fact almost nobody explains clearly

“Moving from Original Medicare into Medicare Advantage is usually easy. Moving back later can be hard.“

Here’s the asymmetry that makes this decision sticky: moving from Original Medicare into Medicare Advantage is usually easy. Moving back later can be hard. You get a one-year trial right when you first enroll — inside that window, you can switch back to Medigap with no health questions asked. Outside that window, in most states, the Medigap insurer can medically underwrite you. A few states (New York, Connecticut) guarantee issue essentially year-round, and others occasionally open narrow windows, but in most of the country, the door back may not stay open. That’s not a reason to avoid Medicare Advantage — it’s a reason to make the first choice deliberately.

The Initial Enrollment Period, and what happens if you’re late

Your Initial Enrollment Period is a seven-month window around your 65th birthday. Miss it without qualifying coverage and the penalties are permanent: Part B adds 10 percent per 12-month period delayed, Part A (if you owe a premium) doubles the penalty period, and Part D adds roughly 1 percent of the 2027 base premium ($41.33) per month you went without coverage — for as long as you have the plan.

What each choice costs for 2027, in short

Part B premium: projected around $209.50/month standard
Part D deductible: $700
Part D out-of-pocket cap: $2,400/year
Medicare Advantage premiums: vary by plan and county, many near $0 beyond Part B
Medigap premiums: vary by plan letter, insurer, state, and age at purchase — request quotes directly

The bottom line for this week

There isn’t a universally correct answer between Medicare Advantage and Original Medicare plus Medigap — there’s a correct answer for your health situation, your travel habits, your finances, and your tolerance for the trade-offs above. There is a wrong way to do this: drifting into whichever plan on autopilot.

Go be bold!

This article is for general informational purposes and does not constitute insurance, financial, or medical advice. Plan availability, costs, and rules vary by state and by year — verify current details at Medicare.gov, 1-800-MEDICARE, or with a licensed insurance counselor (SHIP) before making enrollment decisions.