Lowest setting, yes....always storing it at "zero" or lowest setting able to. At least that's what I was taught everytime I had to get my wrenches calibration checked and certified.
Zero, no (that is what I used to do as well). Last year I did a lot of research getting a higher end torque wrench for smaller stuff like valve covers, and ran into this:
...when storing a torque wrench for an extended period of time, users should always wind it down to the minimum scale setting and never to zero.
A fully loaded torque wrench, left in storage for a long period, can cause a set in the spring, causing it to weaken over time. On the other end of the scale, by completely off-loading the spring, other components within the wrench may move fractionally relative to each other. When you reapply spring compression the orientation of these components can change, therefore affecting accuracy. All in all, it is better to leave a bit of compression in the spring while in storage.
Torque wrenches are common place across a variety of industrial processes, commercial garages and even homes wherever there is a precision assembly process utilising threaded fasteners. Considering their widespread use however, there remains a number
I went down that rabbit hole when I was reading reviews trying to decide between several torque wrenches, finding people that had issues that the factory said was due to completely unloading the torque wrench. You would think they would simply design the tool to unload to lowest setting rather than zero, but they don't.