Carry it once, use it a hundred times.

Ever watch a buddy crank down on a carbon bar without a torque wrench? My friend Mike did that last season. He put all his weight into a 4mm hex, stripping the bolt head clean off. Had to drill it out, ruined a brand-new handlebar. @sarahl68 is right, that click really does save your gear. Now he won't touch a stem without his little wrench.