Why ?
Tbf, when I had xp I tended to do this, it being easier than dealing with the issues from constant installing removing. Still, never had any such need with either vista or w7. If you have to reinstall either of those regularly you need to take a good look at your hardware.
Also, unless something changed, if flash crashes 3.6 should simply offer to reload the tab. The only time I've had stutter was using a beta build but even then, it was flash crashing not ff
