How long do cigarettes last?

I have a number of packs of Virginia Slim 120s stored in boxes in my closet.  Some of the packs are open.  How long are the cigarettes good for, I wonder?  I haven't been smoking.  Have thought about trying them again, but not sure if I should buy a new pack.  Not sure I really want to go back to smoking, but can't get the thought of those delicious smokey treats out of my mind.  Wore cotton boxers today under my mens slacks, but thought about silky nylon panties again.  Thinking about going to a Gay bar, but I'm not Gay!  Been feeling a bit lost actually.