If you've ever had a fastener come loose, break in half, or suffer stripped threads, then it's likely the bolt and nut wasn't properly torqued. Overtighten a bolt and you'll stretch it beyond its tensile strength and the fastener will fail. Undertighten the same bolt and eventually it'll come loose or not provide the clamping force needed to keep your parts bolted together. A torque wrench is a reliable tool for making sure your engine, suspension, or wheels stay put under the high-stress environment of the open road.