You must be totally disabled. Other programs, such as Workers’ Comp or private insurance, may pay benefits for partial or short-term disability, but SSDI pays only for total disability.
Your disability must be caused by a medical condition that is expected to last at least a year or to result in death.
The disability must be severe. The Social Security Administration has a complex system for deciding which disabilities meet its definition of “severe.”
Because of your disability, you are no longer able to do the work you did before.
You are also not able to do any other kind of work. Social Security takes into account your disability, age, education, skills, and prior work experience in determining what kinds of work you can or cannot do.
You must have worked in jobs that were covered by Social Security. That work has to have been long enough and recent enough to qualify under the Social Security Administration’s eligibility formulas.