Benefit period and lifetime reserve
A benefit period, which is sometimes also called a spell of illness, goes from the day you enter the hospital to the day you have been out of the hospital for 60 days running. For example, if you are in the hospital for 10 days, and out for 60, the benefit period is 70 days. If you return to the hospital even on the 71st day, a new benefit period starts.
The lifetime reserve comes to your aid if you need more than 90 days in the hospital during one benefit period. Each day used from this reserve is irreplaceable, and reduces the total number of reserve days due you. Thus, if you are in the hospital for 107 days, your lifetime reserve becomes 43 days—that is, the 17 days above 90 are subtracted from the 60-day reserve.