Q: Why are there Medicare Parts A-D, and which should I have?

A: Here’s a brief overview of how the pieces fit together: The two original parts are called Medicare A and B; Medicare A primarily covers hospitalization and Part B is for outpatient medical services, like doctor’s visits.  Then there’s Part D—as in drug–, which covers prescriptions.

Then there are two pieces that are somewhat optional. There’s part C, also known as Medicare Advantage plans. Those are kind of similar to employer plans, where you have an HMO network of doctors and it also covers prescriptions. It can replace parts A and B.

Corinne Lofchie is an Elder Care Advisor and SHINE Counselor at the Aging Information Center at Somerville-Cambridge Elder Services.

If you choose not to do Part C, there are also Medigap supplemental plans, which cover the gaps in Medicare. So if Medicare covers 80% of a given services, Medigap would cover the other 20%.

When we give people an overview of the different parts of Medicare, we often describe it as two tracks. You can either choose a Part C plan, which encompasses all of your coverage. Or you can have A and B coverage with a drug plan and perhaps a supplement.

It’s really two choices of how you want your coverage to look.  There are a lot of factors involved, but in a general sense, going with Part D and a supplement allows you more freedom, such as not being restricted to a plan’s network of doctors, whereas Part C might offer additional coverage for things like hearing and dental and might be a lower cost.

It’s also important to know that many aspects of Medicare plans change from year to year, so it’s important to review your coverage during the annual Medicare Open Enrollment period, from Oct. 15 to Dec. 7.

The Medicare.gov website has a very useful tool for comparing coverages to see what best fits your needs, but it can be a little overwhelming. One alternative is to call the Aging Information Center at Somerville-Cambridge Elder Services and inquire about meeting with a SHINE counselor to review coverage. SHINE (Serving the Health Insurance Needs of Everyone) is a government-funded program that provides free information and advice on Medicare coverage.

And one other word of advice: if you want to consult a SHINE counselor, call early—because they typically get booked-up fairly quick around the open enrollment period.

Somerville-Cambridge Elder Services (SCES) is a non-profit agency that supports the independence and well-being of older people in Somerville and Cambridge. For more information, check out the Things to Know When Turning 65 episode of Aging Well at the SCES Youtube Channel, or contact the SCES Aging Information Center at for free advice and guidance.