In my old studio, I used a rolling office chair that could be raised and lowered. Most office chairs I could find would only raise or lower 6 or 8 inches, but I found one that would go a foot and a half. This kept me from having to stand (most of the time) and allowed me to roll back a few feet, to get a look, then roll back in to paint.
In our new house, I don't have the studio space set up yet, but did get my airbrush out last night, for the first time in many months. The office chair got fubarred in the move and wound up at the dump, so just grabbed a kitchen chair to sit in last night. Not my ideal choice, but will suffice until I get back in the swing of things and have time to actually set up my space and figure out best to paint.
I have tried standing, and will say, I think it did help when I first started airbrushing, but if I got into a 3 or 4 hour painting session, my back would be killing me at the end of it. Need to find another one of those high rise office chairs.