Definitions for "Lifetime reserve days"
Under Medicare, you have a lifetime reserve of 60 more  days of inpatient services after you use the first 90 benefit days. You must pay a fixed amount for each day of service.
Hospitalization (Part A) under Medicare from the 91st day of confinement through the 150th day. This period of consecutive hospitalization is not renewable; once used, the benefit is gone.
In the Original Medicare Plan, 60 days that Medicare will pay for when you are in a hospital more than 90 days during a benefit period. These 60 reserve days can be used only once during your lifetime. For each lifetime reserve day, Medicare pays all covered costs except for a daily coinsurance ($438 in 2004).