When the time comes to change the battery in my red dot (Bushnell TRS-25, to be exact), will I have to re-zero it, or does the zero stay the same after a battery change? Thank you.
zero should not change. The position of the dot is moved mechanically, not electronically. It never hurts to go ahead and send a load downrange afterwards just for your own peace of mind, though.
don't know about the bushnell. but I can tell you on the fast fire that it does not change. good luck.