Many people are surprised to discover that Medicare actually provides very limited coverage for nursing homes.

In theory, Medicare Part A covers up to 100 days of care in a skilled nursing facility for each spell of illness. However, this is true only if the nursing-home care follows at least a three-day admission to a hospital. Further, after 20 days, you must pay a copayment of $157 a day (although this may be covered by Medigap insurance).

In addition, the definition of “skilled nursing” and the other conditions for obtaining this coverage are quite stringent. As a result, very few nursing home residents actually receive the full 100 days of coverage. In fact, Medicare pays for less than a quarter of long-term care costs in the U.S.

The other program that covers nursing home care – and provides much broader coverage – is Medicaid. But unlike Medicare, not all seniors are eligible for Medicaid. It’s designed for people with limited income and assets, and to be eligible, you must meet strict financial guidelines.

As a result, many people have to spend down their assets or exhaust their long-term care insurance before they become eligible for Medicaid.

Unlike Medicare, which is federal, Medicaid is a joint state-federal program. This complicates matters, because the Medicaid eligibility rules differ from state to state, and they keep changing as different state governments continually tinker with them. (Many states have their own names for the program, such as “Medi-Cal” in California and “MassHealth” in Massachusetts.)

It’s possible to qualify for both Medicare and Medicaid, with Medicare paying part of a nursing home bill and Medicaid picking up the rest.

Because the Medicare and Medicaid rules are very complicated, and because it’s sometimes possible to qualify for Medicaid while still preserving some significant assets, it’s wise to consult an attorney whenever you’re thinking about how to pay for long-term care in a nursing facility.