Medicare Basics

The Four Parts of Medicare

Medicare is split into four parts. Together, they cover hospital care, doctor visits, all-in-one plan options, and prescription drugs. Here’s how each one works.

Part A — Hospital Insurance

Covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health care. Most people pay no premium for Part A because they (or their spouse) paid Medicare taxes while working.

Part B — Medical Insurance

Covers doctor visits, outpatient care, preventive services, and durable medical equipment. Part B has a standard monthly premium set by Medicare each year.

Part C — Medicare Advantage

An all-in-one alternative to Original Medicare offered by private insurance companies approved by Medicare. Most Advantage plans bundle Part A, Part B, and Part D, and often add extras like dental, vision, and hearing.

Part D — Prescription Drug Coverage

Helps cover the cost of prescription medications. You can get Part D as a standalone plan (alongside Original Medicare) or as part of a Medicare Advantage plan.

Enrollment Periods (and How to Avoid Penalties)

Initial Enrollment Period (IEP)

Your 7-month window around your 65th birthday: the 3 months before, your birthday month, and the 3 months after. This is the most important window — missing it can mean lifetime late penalties.

Annual Enrollment Period (AEP)

October 15 through December 7 every year. During AEP you can switch Medicare Advantage plans, switch from Advantage to Original Medicare, or change your Part D plan. Changes take effect January 1.

Medicare Advantage Open Enrollment

January 1 through March 31. If you’re already on a Medicare Advantage plan, you get one chance to switch to a different Advantage plan or back to Original Medicare.

Special Enrollment Periods (SEPs)

Triggered by life events like moving, losing employer coverage, qualifying for Extra Help, or moving in or out of a Medicaid program. These give you a window to change plans outside the normal periods.

Medicare Supplement vs. Medicare Advantage

This is the most common decision people face. The short version:

• Medicare Advantage tends to have lower (or $0) monthly premiums but uses networks and copays. Great if you’re generally healthy and want extras like dental and vision.
• Medicare Supplement has a higher monthly premium but very low out-of-pocket costs and any-doctor flexibility. Great if you want predictable costs and travel often.

There’s no universally “better” option — it depends on your health, your budget, where you travel, and how you use healthcare. Let’s talk through it.