BCRiders comment to the effect that "the more you use it the less you need it" is accurate. For a new and inexperienced mechanic a torque wrench is a great learning tool. There is a general rule that inexperienced mechanics tend to over torque small fasteners and under torque large ones. A torque wrench protects the small stuff and properly tightens the big stuff.

Crank arms on square taper and Octalink/ISIS spindles require WAY more torque than most new mechanics believe. As an illustration, tighten them VERY tight with an ordinary wrench and then be astounded how much tighter you make them when you use the torque wrench.

We get almost weekly threads saying "my crank arm got loose and nearly fell off while I was riding. What should I do?" Answer: you should have installed it correctly the first time.