keli449,
Thank you. I have reached that decision, and I have signed a contract with a law firm. That rule about how much they get paid, and when they get, it is pretty much the same in all states. Federal law controls it.
I'm told by someone in a position to know that California is one of the easier states to get approved for SSDI. At least, it's easier than some other states - like the one I'm in.
I did take it as an encouraging sign that every law firm I called (lots) were all eager to work on my claim. I have a very long and well-documented history of treatment for depression. Currently, I'm on a slew of meds. The lawyers seem to particularly like that.