To qualify under the regular SSDI program one must have contributed to the program over a long enough period to be fully insured and have disability-insured status. People contribute to this program either through having social security taxes withheld from their paychecks or by paying the self-employment tax if they are self-employed.
As a general rule, if a claimant has worked 20 quarters (a three-month period) out of the last 40 quarters before becoming disabled, they are usually insured for disability. Working five out of the last ten years usually satisfies this requirement.
Insured status usually expires after five years from the last date of steady work. This is referred to as the date last insured.
Claimants who apply after the date last insured will have to prove that they were disabled before the date last insured.
If a claimant is age 31 or younger, the quarter requirement is reduced.