There are two parts: Financial and Medical
Financial: There are two basic Social Security programs: Social Security Disability Insurance (SSDI) which is what it says: Insurance – if you have been working full time before you were disabled, you have probably paid enough through taxes to qualify financially, but every case is different. If you qualify, so do minor children you support. A typical benefit is $1,100 per month and additional amounts for minor children in your household who you support. If you win, you can get benefits as far back as a year before the date you first filed. But, every case is different.
Supplemental Security Income (SSI) provides a very small amount of money (less than $850 per month) to people who live at or below the poverty level. If you win, you do get paid for the time you have been waiting to get your case heard.
Medical: There are five hurdles to Medical eligibility.
Are you working? You don't have to be bed-ridden to qualify. This is why so many people who get Social Security benefits may not look like they should qualify if you see them on the street. Only you know how you feel and what you can do. Don't give up hope just because someone else doesn't believe you.
Do you have a medical impairment? Basically this means a diagnosis of something that limits your ability to work. Here, unlike Workers Compensation cases, they don't look at just one injury, illness or consequence. Everything counts. Does pain or pain medication limit your ability to concentrate? Are unscheduled breaks necessary for you? Are you out of breath or fatigued because you can't sleep? It is the combination of things and what a medical professional says about them that matter.
Some medical impairments, like blindness and terminal cancer, are so severe that there are special rules and the case may be processed more quickly. There is a long list of these conditions. Every case is different.
Can you do the easiest job you have done in the past 15 years? They don't just look at the most recent job you have had. If you have had a sit-down job in the past 15 years, it is legally significant even if you have done heavy labor for the past 10 years.
If you can't do your past job, other factors (age, education, job skills and difficulty with English) will make it harder for you to go back into the work force. It does not matter whether you could actually find a job. It is your “vocational profile" and what the medical professionals say your maximum physical capacity is that count.