This news item made me wonder how useful it would be to hoard cartons of cigarettes. Do they 'keep"?
In my experience as a former smoker, at least several months. Once opened, however, not much more than a week or so before they’d start tasting stale, although an inveterate smoker like I was would still smoke them anyway.
Not a smoker, but in the military I’ve gone on extended trips with smokers who brought their own supply to last several months and I don’t recall them ever complaining about the sealed packs going stale.
My wife, a smoker, says that a hardcore smoker doesn’t really care. If they’re jonesing, they’ll smoke anything. She also says that if stored in the freezer, they’ll stay fresher, longer. No exact timeline, though.
I’ve a buddy who smokes, and now and then he actually returns ciggies to the place where he bought them as being “stale” and no longer smokeable. If you want to hoard tobacco, ciggies might not be the way to go about it, unless a humidor is of some benefit to a more or less sealed package.
Right before I entered the Army in 91, my great-uncle Cliff showed me all the stuff he had brought back from his time in the Army during WWII. I can tell you, without a doubt, after 45+ years the Lucky Strikes he had in his old footlocker, were NOT GOOD.
God, I thought I HAD died.
Well, to be fair, Lucky Strikes weren’t all that good even when fresh. 
Gawd. I imagine you could’ve sucked one of those Luckies down in a single good drag–must’ve been like smoking a forest fire.
Speaking as a 35 year old smoker averaging 2 packs a day since high school, at least two years.
However, an open pack will pretty much suck after a month or two.
…and one lone cigarette found under the seat of your car will pretty much always suck, especially if it has brown stains on it.
2 cents
I’ve been a smoker; though I never considered myself an addict and never had “the jones”, I did try to smoke two-year-old cigarettes when I stumbled upon them in an old jacket a few months ago and the experience was wretched. (I didn’t consider myself a smoker then, but I was curious.) Never kept a sealed pack of cigs around for all that long, so I don’t know much about the in between. However, given that the tobacco is just dry plant material, I’d think it’d be like coffee in that you’d probably be OK if you kept it sealed up in the freezer for however long you would want to keep such things.
Cigarettes sent to Germany
After several months, and many duties charged, tastes like crap. 
I think it’s a matter of them being sealed up, though maybe a cigar aficionado can weigh in, I suspect it’s a similar problem. Either a humidor, or very well sealed. I had occasion to smoke a 4-pack of Pall Malls that came in a C-ration accessory pack about 1987, and they were perfectly fine, and they were at least 15-20 years old.