Originally Posted by
cny-bikeman
"So if you're tightening something and it suddenly becomes easier to tighten, back off" I would consider it too late by then. What I have said when training mechanics is that the resistance will increase markedly when it is "tight enough." A lot of it is still experience (ALL of us have stripped a bolt at one time or another) but that guideline seems to help.
I myself very rarely get to the point that a bolt becomes easier to tighten anymore (generally only with Phillips heads, which are crap anyway), and that is because I rounded a few bolts a little bit years back to learn where that point was. The resistance of some bolts, such as crank bolts, will increase markedly before they are "tight enough", so it just takes experience to know when bolts like that are tight enough not to come loose while riding.
The only bolts I've ever stripped badly are those with Phillips heads that are seized tightly. I curse Ford all the time for causing the Robertson head bolt (which is FAR superior to Phillips) to become relatively rare.