Geraldine retired at age 68. She wasn’t worried about Medicare. After all, she had signed up when she turned 65, so she assumed that part of her retirement planning was already finished.

Then she discovered that Medicare enrollment can be more complicated than she realized.

Like many people who continue working past age 65, Geraldine enrolled in Medicare Part A but delayed signing up for other parts of Medicare because she was covered by her employer’s health insurance plan. That decision was perfectly appropriate. In fact, Medicare generally expects people with qualifying employer coverage to make that choice.

But retirement changes the equation.

Why Medicare enrollment may not be complete

Many people think of Medicare as a single program. In reality, Medicare has several parts.

Part A generally covers hospital expenses and is usually premium-free for individuals with a sufficient work history. Because it is free, many workers sign up for Part A when they become eligible at age 65.

Part B covers physician services and outpatient care. Part D covers prescription drugs. Those programs generally require premiums, so workers who already have employer-provided health insurance often postpone enrolling.

As a result, someone may have started Medicare at age 65 without completing Medicare enrollment for all the coverage they will eventually need.

That is exactly what happened to Geraldine.

Medicare enrollment when employer coverage ends

When Geraldine retired, her employer health insurance ended. That event triggered the need to complete the rest of her Medicare enrollment.

Fortunately, Medicare recognizes that many people continue working beyond age 65. Individuals who delayed Part B and Part D because they were covered by a qualifying employer health plan are generally allowed to enroll after retirement without facing late-enrollment penalties.

Medicare may ask for documentation showing that employer coverage was in place. In many cases, however, the process is relatively straightforward.

The key is timing. Waiting too long after employer coverage ends can create problems. Missing enrollment deadlines can lead to premium increases as well as gaps in health insurance coverage.

That is why retirement is a good time to review your Medicare status and confirm exactly which parts of Medicare you already have.

How Medicare premiums are paid

Another surprise for some retirees involves premium payments.

Many people know that Medicare premiums can be deducted directly from Social Security benefits. But that arrangement happens automatically only for people who are already receiving Social Security.

Geraldine had delayed claiming Social Security. Because she was not yet receiving monthly benefits, Medicare could not deduct premiums from a Social Security check. Instead, Medicare sent her a bill.

Later, when Geraldine eventually starts receiving Social Security benefits, she can arrange to have her Medicare premiums deducted from those monthly payments.

For many retirees, that billing process comes as an unexpected part of Medicare enrollment.

Retirement often brings a long checklist of financial decisions. If you are leaving a job after age 65, make sure Medicare enrollment is on that list. Even if you signed up years ago, retirement may be the event that requires you to complete the process.

Medicare enrollment and Social Security are not the same

Note that Geraldine had not applied to receive her Social Security benefits. She could have — as long ago as age 62. And now that she is actually retiring from her employment, she might consider applying for Social Security at the same time. But she might not. She could wait another two years and maximize her monthly Social Security check.

The point here is not to decide (or even counsel) whether Geraldine should apply for Social Security. It is to point out that Medicare and Social Security are separate programs, with separate rules.

Because Geraldine was covered by the Social Security program, she was eligible to apply for Medicare at age 65. That was without regard to whether she applied for Social Security at 62 (the earliest age), 67 (her “normal retirement age”) or some other age between 62 and 70. That tends to confuse potential applicants. And it sets employees like Geraldine up for exactly the problem she now needs to address.

A word about Medicare “Part C”

We don’t want to leave this Medicare enrollment review without mentioning Medicare Advantage, which is sometimes referred to as “Part C”. In another newsletter we’ll try to address the topic more fully. But since we note that signing up for Medicare Part A doesn’t automatically get you Part B and Part D, the absence of Part C from the list is somewhat glaring.

Medicare Advantage isn’t a separate “part” of Medicare at all. It’s just the delivery system for Medicare, and can include Part A, Part B and Part C. Whether it’s right for you is a fraught question, and requires you to make a number of educated guesses. As we note, though, those guesses are fodder for a different newsletter and we’ll leave you hanging — and anticipating.

And thanks, Geraldine, for lending us your story.