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You've probably heard that Medicare enrollment rules are complicated. And it's true—knowing when to sign up, or even if you need to if you working at 65, takes some research. But the good news is that actually signing up for the benefit is a relative breeze.

To enroll, there are three key steps to follow. But before you do anything, be sure you know exactly what kinds of Medicare coverage you want. Part A (hospital insurance) is free to those who have worked long enough to also qualify for Social Security retirement benefits. You can also qualify for free Part A if your spouse qualifies for Social Security.

Medicare Part B covers expenses for doctors, equipment and other outpatient expenses. The Part B application form itself has only a dozen lines for things like your name, address, and Social Security number. Still, it is surrounded by four pages of explanation.

Together, Parts A and B constitute basic or “original” Medicare, which is the coverage choice for some 70% of Medicare beneficiaries. The other 30% opt for Medicare Advantage plans through private insurers. But they still need to sign up first for Parts A (automatic for most enrollees) and Part B. Now here's how to enroll:

1. Start with Social Security. Medicare enrollment is administered by the Social Security Administration, which offers three options for signing up for basic Medicare. Given how important this is, my feeling is that it's best to enroll in person. I suggest you make an appointment at your local Social Security office—don’t just drop in unannounced. You can call 1-800-772-1213 to schedule your visit. Make sure you check out the hours when the office is open.

If you choose not to take the in-person route, you can simply enroll by phone. Just call the number listed above. But be very clear that you want to sign up for Medicare only (assuming that's the case.) The person on the other end of the line is there to handle applications for lots of Social Security benefits as well, not just Medicare. You don't want to accidentally sign up for Social Security as well.

You can also sign up online, which Social Security has been encouraging people to do both for retirement benefits and Medicare. Their online application emphasizes that you need not visit an office. If you do opt for online enrollment, make sure you read this brief guide or view the video that explains how to sign up. The agency also provides a checklist of information you will need before signing up.

2. Take care of Medigap. Once you have basic Medicare in place, you'll need to make decisions quickly on other forms of coverage. If you want a Medigap policy, which covers many things not covered by basic Medicare, you should sign up within six months of getting Part B coverage. During this period, you have what’s called a guaranteed issue right of being able to buy a policy regardless of any adverse existing health issues. You are protected from excessive premiums related to either your age or your age.

If you miss this window, however, all bets may be off. Insurance companies are not required to sell you these policies and can charge you much higher rates if they do. (There are special circumstances, such as losing access to a retiree health insurance policy, that will trigger a 63-day window during which your guaranteed rights are restored.)

3. Consider Medicare Advantage and Part D. If you want a Medicare Advantage plan or a Part D drug plan, their enrollment windows are the same as for Medicare Part B. You must first sign up for basic Medicare before contacting a private insurer for a Medicare Advantage Plan or a stand-alone Part D plan.

Signing up for Medicare would be even easier if the government made additional efforts to educate people about the process and alerted them to their possible upcoming enrollment windows.

Five U.S. House members recently sent a letter to the heads of the agencies responsible for Medicare, asking them to do just that. A spokeswoman for the group said their letter was based in part on a report last fall from the Center for Medicare Rights.

“No federal entity is currently responsible for notifying people nearing Medicare eligibility about the need to enroll if they are not already receiving Social Security benefits,” the report said. After 50 years in business, Medicare can do a lot better here.

Philip Moeller is an expert on retirement, aging, and health. He is co-author of The New York Times bestseller, “Get What’s Yours: The Secrets to Maxing Out Your Social Security,” and is working on a companion book about Medicare. Reach him at moeller.philip@gmail.com or @PhilMoeller on Twitter.

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