Generally, you have to have worked both long enough and recently enough to qualify (paid into Social Security). It may not be sufficient that you worked for many years and paid into Social Security — when you worked is also important. Most people need at least 20 credits earned over ten years (1 credit each three months) .The date on which you would lose your eligibility is called the “date last insured,” which can be found on your social security statement or you can call 1-800-772-1213. If you can prove that you became disabled before your DLI then you would qualify for SSDI benefits. If you cannot prove you were disabled before your DLI then you may be able to qualify for Social Security Insurance, the other disability program under SSA where you have to fall under certain income and resource qualifications.