For known prolonged storage without much use, I try to only use lights with multiple cells for slower overall drain, and I check or maintenance charge them every 1-3 months depending on use. And I keep the charge at around 4 volts (not the max 4,2V).
Alkaline cells are a big no-no for me (been there, leaked that more than once...), so now it's only 18650 or 21700 cells for me. Something with good capacity, and preferably a simple light with no memory / parasitic drain.