I did most of of my fitting myself. Once I had the seat too high when I was given a new saddle, felt unstable, and decided I should stop riding. Dumb mistake, but I was under a lot of stress. I started riding again almost 8 years ago because I had forgotten the instability. I rode a bit and felt unstable again, but this time I analyzed the problem. The saddle changed, so it was likely that something about the new saddle was the problem. Sure enough, the new saddled was taller than the old one. Lowering it cured the feeling of instability.
A few years ago, when I was experimenting with saddles to avoid perineal numbness, I was experiencing knee pain on every ride. At the urging of a couple of physical therapists, I did a one hour consultation with a fitter, not a full fit. He raised my saddle height by a 3-4 CM. I can still get knee pain, but I have so far always gotten out of pain by moving my foot on the pedal.
I think some sort of observer can be very helpful in curing discomfort. I'm not so certain about a full fit, because I think fit changes with conditioning and miles. I sort of think one might need to get a new fit every month.
