The Complete Guide to Medicare
Medicare can be confusing with its multiple parts, enrollment windows, and plan options. This guide breaks it all down so you can make confident decisions about your coverage.
1. What is Medicare?
Medicare is the federal health insurance program for people 65 and older, and certain younger people with disabilities or End-Stage Renal Disease (ESRD). It's administered by the Centers for Medicare & Medicaid Services (CMS).
Medicare is divided into four parts — A, B, C, and D — each covering different services. Understanding what each part covers (and doesn't cover) is essential for making smart enrollment decisions.
The Four Parts at a Glance
2. Medicare Part A: Hospital Insurance
Part A covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health care. Most people don't pay a premium for Part A if they (or their spouse) paid Medicare taxes for at least 10 years (40 quarters).
What Part A Covers
- • Inpatient hospital care (semi-private room, meals, nursing, drugs)
- • Skilled nursing facility care (up to 100 days per benefit period)
- • Home health services (part-time skilled nursing, therapy)
- • Hospice care (comfort care for terminal illness)
- • Inpatient care in a religious nonmedical health care institution
2025 Part A Costs
- • Premium: $0 for most people (up to $518/month if you didn't work enough quarters)
- • Hospital deductible: $1,676 per benefit period
- • Days 1-60: $0 coinsurance
- • Days 61-90: $419/day coinsurance
- • Days 91+: $838/day (lifetime reserve days)
3. Medicare Part B: Medical Insurance
Part B covers outpatient care — doctor visits, preventive services, durable medical equipment, ambulance services, mental health, and more. Everyone pays a monthly premium for Part B.
What Part B Covers
- • Doctor and outpatient visits
- • Preventive services (annual wellness visit, screenings, vaccines)
- • Ambulance services
- • Durable medical equipment (wheelchairs, walkers, oxygen)
- • Mental health services (outpatient)
- • Some home health care
- • Outpatient surgery
2025 Part B Costs
- • Standard premium: $185/month (higher earners pay more via IRMAA)
- • Annual deductible: $257
- • Coinsurance: 20% for most services after deductible
- • No out-of-pocket maximum (this is why Medigap matters!)
⚠️ Late Enrollment Penalty
If you don't sign up for Part B when first eligible and don't have creditable coverage, you'll pay a 10% penalty for each 12-month period you could've had Part B. This penalty lasts as long as you have Part B.
4. Medicare Part C: Medicare Advantage
Medicare Advantage (MA) plans are offered by private insurance companies approved by Medicare. They bundle Parts A and B (and usually Part D) into a single plan, often with additional benefits like dental, vision, hearing, and fitness programs.
✅ Pros
- • Often $0 monthly premium (plus Part B)
- • Out-of-pocket maximum (unlike Original Medicare)
- • Extra benefits (dental, vision, hearing, gym)
- • All-in-one convenience
- • Some plans offer OTC allowances
❌ Cons
- • Network restrictions (HMO or PPO)
- • Need referrals for specialists (HMO plans)
- • Prior authorization requirements
- • Limited coverage when traveling
- • Can't use with Medigap
Types of MA Plans: HMO, PPO, PFFS (Private Fee-for-Service), SNPs (Special Needs Plans for dual-eligible, chronic conditions, or institutionalized individuals).
5. Medicare Part D: Prescription Drugs
Part D covers outpatient prescription medications through private insurance plans. You can get Part D as a standalone plan (with Original Medicare) or as part of a Medicare Advantage plan.
The Coverage Stages
⚠️ Late Enrollment Penalty
1% of the national base premium ($36.78 in 2025) × number of months without creditable coverage. This penalty is added to your Part D premium permanently.
6. Medigap (Medicare Supplement) Plans
Medigap plans are sold by private insurers to fill the "gaps" in Original Medicare — the deductibles, copays, and coinsurance that Parts A and B don't cover. There are 10 standardized plan letters (A, B, C, D, F, G, K, L, M, N).
Most Popular Plans
Plan G — Most Popular Overall
Covers everything except the Part B deductible ($257/year). Best value for most new enrollees.
Plan N — Best Budget Option
Lower premium than G. You pay up to $20 copay for doctor visits and $50 for ER visits (waived if admitted). Plus the Part B deductible.
Plan F — Legacy Plan
Covers everything including Part B deductible. Only available to people eligible for Medicare before January 1, 2020.
💡 Important: Medigap Open Enrollment
You have a 6-month Medigap Open Enrollment Period starting when you're 65+ AND enrolled in Part B. During this window, insurers can't deny you or charge more for health conditions. After this period, you may face medical underwriting.
7. Medicare Eligibility & Enrollment
Who Qualifies?
- • Age 65 or older (U.S. citizen or permanent resident for 5+ years)
- • Under 65 with a qualifying disability (after 24 months of SSDI)
- • Any age with ESRD or ALS
Enrollment Periods
Initial Enrollment Period (IEP)
7-month window: 3 months before your 65th birthday, your birthday month, and 3 months after.
Annual Enrollment Period (AEP)
October 15 – December 7. Switch MA plans, join/leave Part D, or return to Original Medicare. Changes effective January 1.
Medicare Advantage Open Enrollment (MA OEP)
January 1 – March 31. Switch from one MA plan to another, or drop MA and return to Original Medicare + Part D.
Special Enrollment Periods (SEPs)
Triggered by qualifying events: moving, losing employer coverage, qualifying for Medicaid, etc.
8. Medicare Costs Breakdown
| Part | Monthly Premium | Annual Deductible | Cost Sharing |
|---|---|---|---|
| Part A | $0 (most people) | $1,676/benefit period | $0 days 1-60; $419/day 61-90 |
| Part B | $185+ (IRMAA adjusted) | $257 | 20% coinsurance |
| Part C (MA) | $0-$200+ (varies) | Varies by plan | Copays/coinsurance; OOP max |
| Part D | $0-$100+ (varies) | Up to $590 | $2,000 OOP cap (2025+) |
| Medigap | $50-$400+ (varies) | N/A | Depends on plan letter |
💰 IRMAA: Income-Related Monthly Adjustment
If your modified adjusted gross income exceeds $106,000 (single) or $212,000 (married filing jointly), you'll pay higher Part B and Part D premiums. Based on your tax return from 2 years ago.
9. How to Choose the Right Medicare Plan
Decision Tree
Want freedom to see any doctor? → Original Medicare + Medigap + Part D
Want lower costs and extra benefits? → Medicare Advantage (Part C)
Take expensive medications? → Compare Part D formularies carefully
Travel frequently? → Original Medicare + Medigap (more portable)
Want dental/vision/hearing? → Medicare Advantage or standalone plans
List Your Medications
Check each plan's formulary to ensure your drugs are covered and at what tier/cost.
Check Your Doctors
If considering Medicare Advantage, verify your preferred providers are in the plan's network.
Estimate Total Costs
Add up premiums + expected out-of-pocket costs based on your typical healthcare usage.
Consider Your Health Trajectory
If you're healthy now, Medigap is easier to get. Health conditions can make it harder (or impossible) to get later.
10. Common Medicare Mistakes to Avoid
❌ Missing your Initial Enrollment Period
Late enrollment penalties that last forever. Part B penalty: 10% per year delayed. Part D: 1% per month.
❌ Not signing up for Medigap during Open Enrollment
After the 6-month window, insurers can deny you or charge more based on health status.
❌ Assuming Medicare covers everything
Medicare doesn't cover long-term care, most dental, vision, hearing aids, or care outside the U.S.
❌ Choosing a plan based only on premium
A $0 premium MA plan might have high copays and a narrow network. Total cost matters more.
❌ Not reviewing your plan annually
Plans change every year — formularies, networks, premiums, and benefits. Always review during AEP.
❌ Ignoring IRMAA
High earners pay significantly more for Part B and D. Plan income strategically, especially around retirement.
11. Medicare & Medicaid (Dual Eligibility)
Some people qualify for both Medicare and Medicaid — known as "dual eligibles." Medicaid can help pay Medicare premiums, deductibles, and copays, and covers services Medicare doesn't (like long-term care).
Programs That Help with Medicare Costs
12. Frequently Asked Questions
When should I sign up for Medicare?
During your Initial Enrollment Period — the 7-month window around your 65th birthday. If you have employer coverage, you may delay Part B without penalty, but sign up within 8 months of losing that coverage.
Can I have Medicare and employer insurance?
Yes. If your employer has 20+ employees, your employer plan is primary and Medicare is secondary. Under 20 employees, Medicare is primary.
Is Medicare free?
Part A is usually premium-free. Part B has a standard premium ($185/month in 2025). Part D and Medigap have separate premiums. You'll also have deductibles, copays, and coinsurance.
Can I switch from Medicare Advantage to Original Medicare?
Yes, during the Annual Enrollment Period (Oct 15 – Dec 7) or the MA Open Enrollment Period (Jan 1 – Mar 31). But getting Medigap after your initial enrollment window may require medical underwriting.
Does Medicare cover prescriptions?
Only through Part D or a Medicare Advantage plan that includes drug coverage. Original Medicare (Parts A & B) does not cover outpatient prescriptions.
Need Help with Medicare?
Navigating Medicare doesn't have to be stressful. Our licensed agents specialize in Medicare and can help you find the right coverage at the right price.