A high-quality torque wrench is a durable tool that should give many years of service, but they need some looking after. It varies depending on type, so always follow manufacturer's instructions carefully. Most is common sense. Take care not to drop it when in use. Keep it clean. Store in a separate case so other tools can't damage it. Torque wrenches should be recalibrated periodically – once a year is recommended for a regularly used tool. Again, follow maker's advice.