There are many kinds of disability payments out there, and Social Security has its own particular flavor of rules and regulations. First, you must be unable to do ANY kind of full-time work to qualify. If you used to be a brain surgeon and you could still be a parking lot attendant, Social Security doesn’t consider you disabled.
If you qualify, your case is supposed to be reviewed every three to five years. Sometimes this happens, sometimes not. Some conditions are not reviewed, and sometimes the rules change. For example, 15 years ago AIDS cases were rarely reviewed, but now with all the improved medical treatments they are. If you are over 55 or 60, your chances of review are lower. Sometimes judges will recommend that a younger person be reviewed in a year.
No matter what, keep up with your medical treatments and make sure your medical record documents your problems. If your case is reviewed, what you need to prove is that there has been no change in your condition. Most helpful is a letter from your doctor stating that. React quickly if you get a notice of review and seek legal help immediately. If you appeal immediately (do not delay!) send it certified mail, you only have ten days to appeal and keep your benefits flowing while you do.