Another great suggestion for helping to avoid stripped Allen screws is to
ONLY use high-torque Allen keys (from Wera).
I've used these since I was in college, and even for small sizes like 3/32" or 5/64" I've yet to strip one of these Allen keys. I've also been able to use these to remove "stripped" screws that regular Allen keys couldn't get out. They aren't much more expensive than regular Allen keys, so it's basically a no brainier.