How MA actually works
When you enroll in a Medicare Advantage plan, you don't lose Medicare — you redirect it. Medicare pays the private insurer a fixed monthly amount per enrollee (the 'capitation rate'), and the insurer takes over delivering your A and B benefits, plus typically D, plus extras.
You still owe your Part B premium ($202.90/mo standard 2026). You may owe an additional MA plan premium (often $0 — the lowest-premium plans get the most enrollment), or you might get a 'giveback' where the plan rebates part of your Part B premium back to you.
Your benefits come from the plan's network and rules — not Medicare's directly. That means networks, prior authorization, plan-specific drug formularies, and plan-defined cost-sharing.
MA plan types — HMO, PPO, PFFS, SNP, MSA
HMO (Health Maintenance Organization): you must use in-network providers except for emergencies. You'll likely need referrals from a primary care doctor. Cheapest premiums. Most restrictive.
PPO (Preferred Provider Organization): in-network is cheaper but you can go out-of-network at higher cost. No referrals required. Higher premiums than HMO.
PFFS (Private Fee-For-Service): the plan determines payment rates and any provider can choose to accept or decline on a visit-by-visit basis. Less common.
SNP (Special Needs Plan): tailored to specific groups — chronic conditions (C-SNP), institutionalized (I-SNP), or dual-eligible Medicare+Medicaid (D-SNP). Often very low cost-sharing for the target population.
MSA (Medical Savings Account): an HSA-like structure with a high-deductible MA plan. Plan deposits money into your savings account; you pay first-dollar costs from there until you hit the deductible. Few people choose this.
The network reality
MA networks vary widely. A large national MA-PPO might cover 85%+ of providers in your area. A regional HMO might cover only 40-50%.
When you enroll, verify your specific doctors are in-network using the plan's provider directory (and confirm by calling the doctor's office — directories are notoriously stale). If you have a specialist you don't want to lose (oncologist, cardiologist), this matters.
Out-of-network care on an HMO is YOUR cost (except true emergencies). On a PPO, out-of-network has higher cost-sharing (often 40-50% coinsurance vs. 20% in-network).
Networks change. Carriers can drop providers mid-year. There's no guarantee your doctor stays in-network. This is a fundamental difference from Original Medicare, where any doctor accepting Medicare is 'in-network' nationally.
Prior authorization — the friction of MA
About 70% of MA plans require prior authorization for at least some services — and the exact list varies by plan and changes annually. Common services requiring PA: imaging (MRI, CT), surgery, skilled nursing, home health, certain medications.
When prior auth is required, your provider has to submit clinical documentation to the insurer, who decides whether the service is 'medically necessary.' The decision can take days to weeks. Decisions are sometimes denied — and Medicare oversight reports show denial rates of 13-15% for some plans, with many of those being inappropriate denials that get reversed on appeal.
Original Medicare uses prior authorization for very few services. Medigap doesn't add prior auth. So the volume of PA paperwork and delays is a real cost difference.
The OOP cap — MA's killer feature
Every MA plan has a maximum out-of-pocket (MOOP) for in-network services. In 2026, the federal cap is $9,250 for in-network and $14,000 for in+out of network. Most plans set their cap below the federal max — typically $4,000-$8,000 for in-network.
Once you hit the cap, the plan covers 100% of in-network costs for the rest of the year. This is the cap that Original Medicare doesn't have. For people without Medigap, the MA OOP cap is the difference between a manageable medical year and bankruptcy.
Note: prescription drugs are separate. The MOOP applies to A and B services; drugs have their own $2,100 (2026) cap.
MA's extras
Most MA plans include benefits Original Medicare doesn't: routine dental cleanings + some restorative dental, vision exam + glasses allowance, hearing exam + hearing aids, fitness benefits (Silver Sneakers), OTC allowance ($30-100/quarter for over-the-counter health items), transportation to medical appointments, sometimes meal delivery after a hospital stay.
These extras are real value, but evaluate them honestly: a $1,200 dental allowance is great if you use it; useless if you've never been to a dentist. Don't pick a plan based on extras you won't use.
The MA-PD vs MA-only distinction
Most MA plans (about 90%) bundle Part D coverage. These are 'MA-PD' plans. A few MA plans don't include drugs ('MA-only'), typically MSA plans or some PPO plans. If you're on an MA-PD plan, you can NOT also enroll in standalone Part D — Medicare will auto-disenroll you from the MA plan if you do.
If you're on an MA-only plan, you SHOULD enroll in standalone Part D — otherwise you're risking the late-enrollment penalty.
When MA makes sense
MA tends to win for: people with low-to-moderate utilization (a few doctor visits a year), people in markets with strong MA networks (urban areas, especially), people who value the extras (dental, vision, gym), people willing to navigate prior auth and networks for the lower premium.
Original + Medigap tends to win for: high-utilization or chronic-condition seniors, people with specialists they don't want to risk losing, people who travel between states (Medigap follows you nationally; MA networks don't), people who hate fighting insurance for approvals.