How and when to enroll in Medicare Part A and Part B if someone wants to continue in a managed care plan

The person may be one of the many people under age 65 enrolled in a managed care health plan. The company that runs that plan may also have a Medicare Part C Medicare Advantage managed care plan that she could switch to when she turns 65. That would let her continue with all the same doctors and other providers from whom she receives care now. If she's happy with her managed care plan, and the same company offers a Part C Medicare Advantage version, she can simply notify the plan of her intention to switch to this Medicare Part C version. If she does so and isn't already receiving Social Security or other federal pension benefits, the managed care plan will help her enroll in Medicare Part A and Part B.

Automatic enrollment in Medicare Part B if someone is already receiving Social Security or other federal pension benefits

If the person is already receiving Social Security, Railroad Retirement, or federal civil service pension benefits -- retirement, disability, or dependents' or survivors' -- when she turns 65, Social Security will automatically enroll her in Medicare Part B. About three months before she turns 65, Social Security will mail her an initial enrollment period package, including notification of her enrollment in Medicare Part B. If she doesn't want to enroll in Medicare Part B, there's a place on the form where she can decline Part B coverage.

Her Part B coverage will begin on her 65th birthday. If she doesn't receive the documents by two months before she turns 65, she should contact the Social Security Administration at 800-772-1213.

Everyone who enrolls in Medicare Part B must pay a monthly premium for Part B coverage. In 2008, the basic monthly premium most people pay is $96.40. However, if she has over $82,000 in income (over $164,000 for a married couple), the amount is higher. Part B premiums are automatically deducted from her monthly Social Security check. If she isn't receiving Social Security benefits, Medicare will send her a bill every three months.

How and when to enroll in Medicare Part B if someone isn't yet receiving Social Security or other federal pension benefits

If she's turning 65 but isn't yet collecting any Social Security or other federal pension benefit, she needs to sign up for Medicare Part B at a local Social Security office. (She can do it at the same time she files for Social Security benefits at age 65, if she's doing that, too.) In the months immediately before and after her 65th birthday, she has what's called an initial enrollment period. This allows her to sign up for Medicare Part B as early as three months before the month she turns 65, and anytime within three months after the end of the month she turns 65. If she doesn't sign up for Part B by the end of this initial enrollment period, she has to wait until the general enrollment period of January 1 through March 31 each year.

The timing of her enrollment in Part B determines when her coverage begins and can affect how much it costs:

• If she signs up for Medicare Part B within the three months before the month in which she turns 65, her coverage will begin on her 65th birthday.
• If she signs up within three months after the month she turns 65, her coverage will be delayed one to three months; there's no retroactive Part B coverage back to her 65th birthday.
• If she signs up for Part B in the general enrollment period January through March, after her initial enrollment period is over, her coverage won't begin until July 1 of that year. Also, her monthly premiums for Part B coverage will be higher -- 10 percent higher for each year she delayed enrolling.