Re: Drain bolt
It's a crush washer. It's job is the same as a crush washer in the brake system, or like a gasket. It's deformation under proper torque helps seal the surfaces so no leakage occurs. It also prevents overtorque of the the bolt threads and recepticle threads. In other words it prevents stripping, or worse yet, cracking the pan.
I don't reuse gaskets. I won't reuse crush washers either, especially since they are cheap! I don't remember what the service manual says, but I would guess single use only. Buy two now, so you'll have the extra when it's convenient! Oh, did I say they were cheap?!!! (I just bought two manifold gaskets for my car at $8 each. I think I paid 15 cents apiece for a handful of these crush washers last time, however by now the price could be up to 25 cents each!)
I have to agree that technique and proper tools are key. A short 6-point socket for this application is best. In 36 years of doing oil changes for my bikes (and cars) I've never had a bolt round off.
Official Racer Dude Guy, according to a neighborhood 6 year old.