It's the length of time for which you're eligible to receive monthly benefits while you have an illness or injury that keeps you out of work. Policies commonly pay for 2, 5 or 10 years or even to retirement age. The longer the benefit period, the higher the cost will be. A 5-year benefit period would cover the average duration of long-term disabilities across age groups. But depending on your age and health, a policy that covers you to age 65 (i.e., pays for a permanent disability) and gives you extra peace of mind might not cost that much more.