I’m guessing you’re in your 40’s as most people are on here. You will be in your 60’s when you have to worry with your stash turning to shit after you open it. You will be slowing down, with more time on your hands as you reach retirement. Don’t worry so much. But, know that there is risk. Anything with a pay out comes with risk.
I assume that in 20 years, tobacco won’t even be grown commercially any more. And, I’ll be in my 70’s close to 80 if I even live that long. So I don’t give a shit. I just hope my kids don’t stash me in somewhere where I can’t even smoke. That’s more of a worry to me than shitdust. I don’t know anyone over 70 NOT in a living facility.
20 years, so much can happen. Stuff we felt was important at 30 or 40 is no longer even a thought.
I don’t have an optimism about pipes lasting into the 2040’s. Just cellar away, so that it CAN be there of you want to smoke. When and if shitdust becomes a worry, deal with it latter. There’s nothing you can do now. Except if you don’t set any back, your double screwed of tobacco goes the way of the dodo.
I'm in my mid-30's, rapidly moving past the "mid" part. So far, I have been gradually cellaring without making it a big concern, and I'll probably just keep doing exactly that.
I also have contrary view on future availability. I don't think smoking is going anywhere. Look at all the college aged kids who are vaping now. Nicotine and tobacco are still popular, despite every effort to restrict them. I don't know how long it will take, but I think the effort to ban them all completely or regulate them out of existence will lose steam. There was a certain momentum generated in the 80's and 90's because of the horrendous misconduct of the tobacco industry in previous decades in concealing the risks of smoking, but as smoking is becoming more of a niche thing, it's less of a public health issue. Now I do expect prices and taxes to go way up, but that's another thing.
Note that Simon said "If not jarred up ....." I'm not a chemist but will make the assumption the reintroduction of oxygen to the leaf causes it to break down. Not unreasonable to think that. But what's the big deal with jarring an old tin that's been opened?
Given that cellaring deep now is a hedge against availability and significant price increases, what other reasonable alternatives are there?
I'd also point out there is very limited data points to make any conclusion. I've opened several tins of McClelland from the 90's (Christmas Cheer and Bombay Extra) that tasted more full and rich than fresh tobacco. I only put the lid back on and the tobacco was just as good several months later. I had some Mac Baren Virginia blend gifted to me that was from the 70's in a jar. It blew my socks off, I couldn't believe how rich and strong it was and how sharp the flavors were. I screwed the lid back on and smoked on it for several months, no problem.
I also haven't heard how these decades old tins were stored? On a store shelf? In a garage with no temperature or humidity control? Is the seal on tins made these days better or worse than they were decades ago? Again, there is a lot of missing data from very limited data points. Certainly not enough data to draw any kind of accurate conclusion.
My point is there's nothing I see here that would even come close to making me panic over my cellar. Harris is consistently, day in, day out, smoking tobacco that is over 10 years old and has reported zero problems that I know of.
That's all very encouraging, and I agree, there isn't much alternative if you want to be absolutely certain you'll have good blends to smoke in the future, and of course agree with your point about limited data. The limited data is really why I made this post - to see if I can gather a bit more data.
I do think anyone trying to build a decades-deep cellar does need to consider the experiences of those who have seen old tins pretty much die within a day or two of opening. Likewise, I am very encouraged to hear of decades-old tins that have better withstood the test of time.