A couple of years ago I bought an ATN 390 Paladin, economy Generation 1 night scope for my AR15 in 6.8, to pop feral hogs with. Used it a few times, worked well out to 100 yards or so, then put the rifle/scope in the rack and went on to other things. Took the batteries out of the scope and IR attachment ( which about doubles the vision range on moonless nights) . Didn't want to use it again until last week, when hogs came back. Reinstalled the batteries and went out in the evening to sight in. Blank... nothing showed except the red crosshairs; put in new batteries, same result. Long story short, and the moral of the story... ATN customer service told me that long periods of non-use atrophy the chemical reactions inside the scope... said it was a common problem among hunters, who use the device once a year, like I did. Fortunately, I was still barely within the 2-year warranty period, so they're repairing the scope. Turn on the scope for an hour or so monthly, to keep it working.