Each year, at the end of the year, I change all the batteries in my optics.
Yea yea, I know someone is going to point out how my beloved Aimpoint optics have a crazy long battery life. But, in the big picture, batteries are cheap enough that I can make sure there won’t be any unexpected surprises by changing them out at the end of each year.
I want to make sure all these optics will work when I need them too. I also want to make sure that a battery wont get too old and leak nasty chemicals all over the place. I’ve had that happen before, I don’t need it happening again.