us tough, rough, manly and ready blokes just use our eyes and switch off.
those propellar heads use auto shut offs.
or to put it another way,
bird and wombat have the brains to build data loggers and sensors that feedback and switch off / on automatically. the rest of us are just plain lazy!!!
i switch off say at least 1/2 degree ambient and then let it settle. Birds is the ultimate in the way it monitors the lot and automates everything.