Originally Posted by FeltF2Tarmac

A torque wrench in regular use doesn’t need to be wound back. If you expect to store a torque wrench for more than a few weeks, always wind it down to the lowest scale setting (never to zero).

Storing a fully loaded torque wrench can result in a set in the spring, weakening the spring over time. But if you completely offload the spring to the zero setting, other components within the wrench may move a little. And in the world of torque, a little is a lot. Reapplying spring compression will shift orientation of these components, affecting accuracy.

This is from one of several web sites that specifically say never zero the wrench. FYI, if I turned in a torque wrench set to zero at Boeing, it probably would start a line check on every airplane it was used on going back to last recal. Personally, I owned a Snap On torque wrench that did not require any adjustment prior to storage, it required recalibration a lot. More so than any wrench I’ve ever used.