If you are paying for your own insurance, you may think you do not need to sign up for Medicare when you turn 65. However, not signing up for Medicare Part B right away can cost you down the road.

You can first sign up for Medicare during your Initial Enrollment Period, which is the seven-month period that includes the three months before the month you become eligible (usually age 65), the month you are eligible and three months after the month you become eligible. If you do not sign up for Part B right away, you will be subject to a penalty. Your Medicare Part B premium may go up 10 percent for each 12-month period that you could have had Medicare Part B, but did not take it. In addition, you will have to wait for the general enrollment period to enroll. The general enrollment period usually runs between January 1 and March 31 of each year.

There are exceptions to the penalty if you have insurance through an employer or through your spouse’s employer, but there is no exception for private insurance. The health insurance must be from an employer where you or your spouse actively works, and even then, if the employer has fewer than 20 employees, you will likely have to sign up for Part B.

If you don’t have an employer or union group health insurance plan, or that plan is secondary to Medicare, it is extremely important to sign up for Medicare Part B during your initial enrollment period. Note that COBRA coverage does not count as a health insurance plan for Medicare purposes. Neither does retiree coverage or VA benefits.

For a New York Times column about a man with private insurance who didn’t realize he needed to sign up for Part B, click here.

For more information about Medicare and turning 65, click here.

Hospital patients who need additional care after being discharged from the hospital are usually sent to either an inpatient rehabilitation facility (IRF) or a skilled nursing facility (SNF). Although these facilities may look similar from the outside, Medicare offers very different coverage for each. While you may not have complete say in where you go after a hospital stay, understanding the difference between the two facilities can help you advocate for what you need and know what to expect with regard to Medicare coverage.

An IRF can be either part of a hospital or a stand-alone facility that offers intensive physical and occupational therapy under the supervision of a doctor and nurses. IRFs offer a minimum of three hours a day of rehabilitation therapy. An SNF, on the other hand, provides full-time nursing care. Patients also receive physical and occupational therapy, but the care is generally less intensive and specialized than in an IRF.

IRFs and Medicare

Medicare Part A covers a stay in an IRF in the same way it covers hospital stays. Medicare pays for 90 days of hospital care per “spell of illness,” plus an additional lifetime reserve of 60 days. A single “spell of illness” begins when the patient is admitted to a hospital or other covered facility, and ends when the patient has gone 60 days without being readmitted to a hospital or other facility. There is no limit on the number of spells of illness. However, the patient must satisfy a deductible before Medicare begins paying for treatment. This deductible, which changes annually, is $1,364 in 2019.

After the deductible is satisfied, Medicare will pay for virtually all hospital charges during the first 60 days of a recipient’s hospital stay. If the hospital stay extends beyond 60 days, the Medicare beneficiary begins shouldering more of the cost of his or her care. From day 61 through day 90, the patient pays a coinsurance of $341 a day in 2019. Beyond the 90th day, the patient begins to tap into his or her 60-day lifetime reserve. During hospital stays covered by these reserve days, beneficiaries must pay a coinsurance of $682 per day in 2019.

To qualify for care in an IRF, you must need 24-hour access to a doctor and a nurse with experience in rehabilitation. You must also be able to handle three hours of therapy a day (although there can be exceptions).

SNFs and Medicare

Medicare’s coverage of skilled nursing care is more limited. Medicare Part A covers up to 100 days of “skilled nursing” care per spell of illness. Beginning on day 21 of the nursing home stay, there is a copayment equal to one-eighth of the initial hospital deductible ($170.50 a day in 2019). However, the conditions for obtaining Medicare coverage of a nursing home stay are quite stringent. Here are the main requirements:

• The Medicare recipient must enter the nursing home no more than 30 days after a hospital stay (meaning admission as an inpatient; “observation status” does not count) that itself lasted for at least three days (not counting the day of discharge).
• The care provided in the nursing home must be for the same condition that caused the hospitalization (or a condition medically related to it).
• The patient must receive a “skilled” level of care in the nursing facility that cannot be provided at home or on an outpatient basis. In order to be considered “skilled,” nursing care must be ordered by a physician and delivered by, or under the supervision of, a professional such as a physical therapist, registered nurse or licensed practical nurse. Moreover, such care must be delivered on a daily basis. (Few nursing home residents receive this level of care.)

A new spell of illness can begin if the patient has not received skilled care, either in an SNF or in a hospital, for a period of 60 consecutive days. The patient can remain in the SNF and still qualify as long as he or she does not receive a skilled level of care during that 60 days.

Keep in mind that some or all of Medicare’s deductibles and co-payments for both IRF and SNF care may be covered by Medicare supplemental insurance, also called Medigap coverage.

You are turning 65 and enrolling in Medicare, but as a healthy senior do you really need to also sign up for Medicare’s supplemental coverage? Not signing up initially can be very costly down the road.

Medicare pays for only about half of all medical costs. To augment Medicare’s coverage, you can purchase a supplemental or “Medigap” insurance policy from a private insurer. There are 10 Medigap plans that each offers a different combination of benefits, allowing purchasers to choose the combination that is right for them. In addition, Medicare offers a federally subsidized prescription drug program, in which private health insurers provide limited insurance coverage of prescription drugs to elderly and disabled Medicare recipients.

Purchasing the supplemental coverage means paying more premiums. If you don’t go to the doctor very often or have any regular prescriptions, you may not want to sign up for the additional coverage. However, if you get sick, what Medicare doesn’t cover can be a lot more costly than the extra premiums. And buying coverage after you get sick can be difficult and expensive.

You cannot be denied a Medigap policy for pre-existing conditions if you apply within six months of enrolling in Medicare Part B. If you don’t buy a policy right away, the plan can use medical underwriting to decide whether to accept your application. The plan will look at your age, gender, and pre-existing conditions and can charge you higher premiums, restrict coverage, or even reject your application.

Beneficiaries who enroll in Medicare Advantage plans can’t also buy a Medigap policy. But if they chose Medicare Advantage as their first form of insurance and later decide to return to original Medicare, they must select a Medigap policy within the first year of their initial Medicare enrollment or risk being shut out of a policy. (For more on when a Medigap insurer must sell to you, click here.)

Medicare beneficiaries are also subject to significant financial penalties for late enrollment in the Medicare drug benefit (Medicare Part D). For every month you delay enrollment past the Initial Enrollment Period, the Medicare Part D premium will increase at least 1 percent. For example, if the premium is $40 a month, and you delay enrollment for 15 months, your premium penalty would be $6 (1 percent x 15 x $40 = $6), meaning that you would pay $46 a month, not $40, for coverage that year and an extra $6 a month each succeeding year.

There are some exceptions built in to both Medigap and Medicare Part D if you did not enroll right away because you had other coverage. But if you choose not to enroll because you think you won’t need the plan, it is not easy to change your mind later on.