Medicare 101: What You Need to Know

Note to patients: As of Jan. 1, 2024, Scripps Clinic and Scripps Coastal Medical Groups no longer accept Medicare Advantage HMO plans.

Make changes during open enrollment, learn deadlines

Happy Older Couple

Make changes during open enrollment, learn deadlines

Whether you’re new to Medicare, thinking about switching plans or assisting someone to enroll, navigating Medicare can be confusing. Our glossary of common Medicare terms can help you understand your options so you can choose a plan that best fits your needs.

If you are turning 65 or retiring in the near future, and are enrolling in Medicare for the first time, you can sign up during the Initial Enrollment Period. This seven-month window begins three months before your 65th birthday and ends three months after it. If you don’t sign up when first eligible, you may have to pay a late enrollment penalty for as long as you have Medicare.

If you’re already enrolled, you can make changes to your plan once a year during the Medicare Open Enrollment Period, October 15 through December 7. Medicare plans and regulations are updated every year, so review your options during this time. Your coverage will begin on January 1 as long as you enroll in the plan by December 7.

Learn more about Medicare plans, know your options

Check out our list of Medicare terms and learn steps you can take to better understand your options and make sure you get the most from your health plan benefits.

Original Medicare

Original Medicare is made up of two parts. Part A provides your hospital insurance. Part B provides medical insurance for things like doctor visits and checkups. Everyone can have Part A, regardless of whether you’re still employed.

If you’re still working at 65 and are covered by your employer’s health insurance, you may not need to enroll in Part B. Compare your employer coverage with Medicare coverage to help you decide which is best for you. Once you stop working, you’ll have a special enrollment period of eight months after your employment ends in which to sign up for Part B.

Medicare Advantage

Medicare Advantage plans, also known as Plan C, are typically HMO (Health Maintenance Organization) or PPO (Preferred Provider Organization) products. These insurance plans combine the benefits of Original Medicare Parts A and B. They may also include prescription drug coverage (Part D) and extra benefits and services for an additional cost. These plans usually require the patient to access a limited physician network for services.

If you’re enrolled in a Medicare Advantage plan, you can enroll or switch to a different plan during two open enrollment periods:

Prescription drug coverage

Medicare Part A and Part B do not cover prescription drug benefits. For prescription drug coverage you can enroll in a prescription drug coverage or Part D plan. Drug coverage is often included in Medicare Advantage Plans.

Medicare imposes a penalty for late enrollment in Part D plans once you are covered by Part B. Also, Part D drug plans may have very different formularies, so be sure to check that the drugs most important to you are covered by the plan you choose.

Medicare Supplemental insurance (Medigap)

This coverage is an alternative to Medicare Advantage plans and allows individuals to customize their health plan coverage. These plans help fill “the gap” by partially or fully covering expenses that would normally be payable by the patient under original Medicare.

Supplemental plans are only available to purchase for people who are enrolled in Original Medicare. People with a Medicare Advantage plan cannot buy Medicare supplemental insurance.

Once you have evaluated your choices, choose the Medicare plan that is the best fit for you and complete the enrollment process. You may be able to sign up in person with a broker, through the mail, over the phone or online.

Already enrolled but want to switch plans?

If you’re enrolled already, you’ll need to decide whether you want to change your coverage and be aware of important deadlines.

Review your existing health and drug benefits and pay attention to any changes announced for the coming year. Your current insurance provider will send information to let you know what, if any, changes will be made to your Medicare coverage.

Review these carefully to ensure the providers, services and medications you need are covered and at what cost. Check your premiums, coinsurance, co-payments, deductible and out-of-pocket limits, and ask yourself whether another plan would better suit your needs in the coming year.

If you have employer or union coverage, check with your plan’s benefits administrator before making any changes to your coverage. Otherwise, you could lose coverage for yourself and your dependents.

Finally, take advantage of the benefits your plan offers. Your Medicare coverage offers more than just sick care. Review your benefits and take advantage of wellness and preventive services, such as an annual exam, weight and blood pressure check, flu shots and more.


If you are in a retiree plan, your former employer may be a good source of information about your Medicare options. The following may also be resources in your search for information about Medicare enrollment, benefits and other helpful tools:

Take care of your health

According to the Centers for Disease Control and Prevention (CDC), older adults and people who have severe chronic medical conditions, such as heart, lung, or kidney disease are at higher risk for severe illness from COVID-19.

See how Medicare is responding to COVID-19 and what older adults can do to protect their health during the pandemic.

Related tags: