I once stripped out an expensive BB and that sealed the deal for me. Been using a torque wrench ever since. After many years of building/repairing bicycles using a torque wrench I know most torque specs off the top of my head. I'm a perfectionist, the kind of mechanic that YOU want building your bicycle but a shop owner hates to employ a guy like me. I'm not fast enough for most shop owners but you can bet your last dollar that a bicycle I build/repair for a customer won't come back in for the same repair twice due to my error. I now wrench for my own pleasure and run a small bicycle repair business out of my home. I even make house calls