Medicare Advantage can be a one-stop shop for health insurance after age 65. Original Medicare includes Part A (hospital coverage) and Part B (for doctors and outpatient services). You can buy Part D drug coverage separately through an insurer. Medicare Advantage (Part C) consists of private, managed-care plans that offer Parts A and B and often D. Which is right for you? It depends on your preferences and your situation.   

Only about a third of Medicare Advantage plans charge premiums. Original Medicare covers 80% of services and has no cap on your out-of-pocket costs. With Medicare Advantage plan, you also have to share some costs. But they're usually less than with Original Medicare, and out-of-pocket expenses are capped. Most include drugs, so you don’t need a separate Part D plan. If you have Original Medicare, the average Part D premium is $44.

It varies depending on where you live. But the average beneficiary has 39 Medicare Advantage plans to choose from. They may include:

• Health Maintenance Organization (HMO) plans
• Preferred Provider Organization (PPO) plans
• Private fee-for-service plans, which allow more flexibility in choosing providers
• Medical Savings Account plans

Before you buy a plan, compare prices and coverage. And check whether your doctors are in-network.

Most Medicare Advantage plans require you to use a certain group of doctors, called in-network providers. This limits your choices, especially if you're in a rural area or have a serious health condition. You might face long waits for appointments, or long drives to provider offices. You may be able to go out of network, but you’ll pay higher out-of-pocket costs. With Original Medicare, you can see any doctor who accepts Medicare.

Unlike Original Medicare, many Medicare Advantage plans require referrals for specialists. Many also require prior authorization for at least some services, like hospital stays and pricey medications. This can delay treatment, especially if you:

• Need to see many specialists
• Must follow “step therapy” (try a generic drug to see if it works before you get coverage for a pricier treatment)
• Fight coverage denials

With Original Medicare, you can go to any doctor or hospital in the US and its territories that takes Medicare. Most Medicare Advantage plans only cover care in your plan’s service area, unless you have to go to an emergency room or urgent care clinic. If you spend part of the year in another state, for instance, it may be difficult or very expensive to get medical care there. 

Medicare Advantage plans tend to offer extra benefits, like dental care, eye exams, hearing aids, telehealth visits, fitness programs, and even acupuncture. These vary widely from plan to plan, and there may be co-pays for these services. Some Medigap plans have also started offering extra benefits.

Doctors and hospitals can choose to leave a Medicare Advantage plan from one year to the next. That could mean you have to look for new doctors, or pay the higher costs of going to providers who are no longer in-network. The plans' drug coverage can also change. Medications you use now might no longer be covered in the same way. Bonus features that attracted you to a plan could be dropped or changed, too.

It’s fairly easy to switch from Original Medicare to an Advantage plan or from one Advantage plan to another during Medicare's Open Enrollment Period. It’s trickier to go from an Advantage plan back to Original Medicare if you also want Medigap insurance. You can be denied if it’s been a year since you first enrolled, and you have serious health problems.

Studies show that both Medicare Advantage plans and Original Medicare deliver good care. But there are some caveats. For instance, Medicare Advantage plans get better ratings for preventive care, but not on other important measures, like:

• Patient experience
• Racial and ethnic disparities
• Hospital readmission rates

One report found Advantage plans sometimes wrongly deny prior authorization for care that meets Medicare coverage rules.