You do not need to reset offsets after the machine has been turned off. The axis homing sequence (Auto Restart) finds the same location every power up to within better than 0.0002".
We run machines for weeks without doing anything to offsets.
But, having said that, I have had funny things happen with rotaries. On two occasions I have had one home to a different position but that is twice in several years of use. Now I do a quick check on my rotary just to be safe.
An open mind is a virtue...so long as all the common sense has not leaked out.