Battery storage in flashlight

How long is it ok to keep batteries in a seldom used flashlight? does brand have anything to do with it?

many trains of thought and no determinations on this.
you see a perfectally good alkaline could spew all over your light right out of the blue. a lithium primary is good for 10 years, but some flashlights could completly depleate a cell because of the curcuit type, or a curcuit failure even.

if i had a recomendations it would go like this:

Shelf Queen, put matched cells in when you want to show it off

Dead lights, if the batteries went down, good time to throw them out, especially alkalines, of course not rechargables

Standard storage, dont bother having excessive quantites parked of any battery,for time weighs on most of them. used matched sets as matched, dont just plunk any 2 cells in a light cause it was in the pile where the good ones are suppsed to be (yup you know i have done it too)

Emergency light, check often, or store cells next to it in battery holder of any variety, in this situation TIE the batteries TO the light, and put a combination lock on them cause you will never find them or who just put them in a toy if you dont .

Alkaline holding lights, open em up every 3 months look for any discoloration on the wrapper, or white formations at the ends, these can be clues to them leaking someday, and could prevent light damage when the leaking is allowed for longer time.

Click on click off, a quick check of the light can give you a slight clue, as totally dead batteries especially alkaline will leak faster.

see if you can use ni-mhy type batteries, they leak much less often, and can be recharged so you know they are ready to use
if you use lithium like the 123 cell checking would be way less often.

know for a fact if the type of curcuit you have in your light uses picoamps (teeney leetel amps) to do its curcuit trick, Hard switches, and disconnecting things dont use power cause full disconnection occurs, but some controllers , often soft switch, need to watch for switch presses, and could depleate a cell in about 2 months. check with a meter if you got one.

Twist tail ons, recommendations to twist tail out further (as high as 2.5 turns) when being stored, so turn on does not occur.
same idea , lots of lights with normal switches you can twist off the head or tail a bit and put it into lockout.

Brands, well no determination on this for alkalines that i can find, energypters, ray-o vacumes, durasell, all can leaks, BUT the top brand manufactures ALSO fully back up thier producs. ni-cds and ni-mhy and lithium, and li-ion are VERY rare to "leak".

Use it or lose it, almost every item that you use often, you check more, and or your more likly to put in rechargables, it is often the items you dont use or maintain in any way that are the ones allowed to get so far off.

Thanks a ton for your input it is very helpful to me.