I have a one 1/2" MAC click-off style since the sixties and instructions then were to leave it rest @30ft lbs. I have a MATCO 1/4" that I have never used and can check the instructions.
Most tool trucks can send them out for calibration (and yes it is good to check on a scheduled basis). I think I have the name of a calibrater here...I will have to try and find it.
I understand the new models can be left at whatever setting, but all of this depends upon quality of the tool.