May we all be well enough to plan for this!
I don't know about social security disability.
My company plan had a pre-existing condition clause where you had to wait some number of months before you were covered, at least for the pre-existing condition, I can't recall the details. Family medical leave and Short Term Disability work by accrual, I believe, so you'll have to work a while before they are something you can fall back on.
Personally, if I ever get well enough to work again I'm going to research the topic really, really well before getting myself into a situation where I could lose a benefit I previously had. I'll spend some bucks on an attorney to make sure I don't wind up worse off.
I would advice anyone considering going back to work to spend at least several weeks simulating what the job you intend to do by walking, standing, driving, computer time, etc., to be sure you're ready before you drop your disability income.
