If you received the short form and haven't seen a doc about whatever qualified you for SSI or SSDI, then you will likely be sent the long form CDR in the next 6 weeks or so. (Or perhaps, you already have the long form.)

The long form CDR process is comparable to going through the original application process to qualify for SSI /SSDI. SS will likely send you to a consulting doc/s paid by SS. Sometimes applicants/recipients are very unhappy with the results of those exams. Sometimes the exams are very rushed.

SS used to have less stringent requirements for SSI recipients that qualified as children, and allowed them to continue receiving benefits as adults. For certain conditions, it is now much more difficult to continue receiving benefits.

So, there are lots of factors that could make the CDR process more complicated than you'd imagine. The suggestions given here by several of us are to try and prepare you for a worst case scenario, so that you are not blindsided. If your benefits are ceased, you will be able to appeal, but having current medical records would likely be necessary.