I never had to go in front of a judge to get SSDI approval, but like Christina wrote, having my psychiatrist and therapist fully on board with my application was surely crucial to my getting approval. I would, personally, definitely want some letter and/or form filled out by both (or at least my psychiatrist) if/when I ever have to.

Like Moose wrote, the more evidence of difficulties with the illness, the stronger the case, likely. I had had 10 psych hospitalizations and 12 PHPs/IOPs in the 3.5 years prior to my SSDI approval, spending more than 12 of those months total in the hospital and IOP combined. I had also eventually been terminated from my job for being out on private long-term disability so long. I had attempted to return to work at least four times during that period (only once making it beyond part-time) with little success, so returning to work even part-time was destabilizing for me. I have had varying levels of struggle even since getting SSDI, including abandoned volunteering attempts due to relapse, etc. Documenting all of this is important.