What we're discussing is the amount of aging that pleases our palates, and what we like sets that bar, the tobacco not withstanding? What we like decides which tobacco ages best, and at what point it is best.
True. But there's a perception that tobaccos just get "better and better" with age, and it's just not true, any more than it is with wine. At some point everything peaks and then heads downhill. The "everything just gets better and better" is a boon to people selling old tins to a gullible new market. It's not a boon to buyers.
Pease has also written that the most dramatic part of the aging process happens in the first few years and after that it becomes more incremental. To me, that means that I can get a great smoke without having to wait eons. And frankly, a well constructed blend is worthwhile fresh.
Some get to feel superior because they only smoke well aged tobacco, 10 to 15 years for example, and they like to say how you haven't really experienced blend "x" until you've had it well aged. Maybe, but after having smoked a lot of well aged tobacco over the years I think it's mostly BS.
The tobaccos will be different, but they're going to be something subtly different, not the Second Coming. And sometimes that difference isn't really an improvement. Again, it depends on what you like. I know smokers who prefer their Escudo fresh to aged. I like it both ways. But I don't experience aged Escudo as some rapturously better blend.
So when does tobacco peak and then begin to fade? Hell if I know. But I have a personal rule which is that anything older than 25 years is a coin toss. I'm not saying that tobaccos can't live longer than that, but that the results in the tin become more variable, probably because of how its been stored. And after 30+ years, flavors are generally less robust, not more. At 40+ years it's like smoking wraiths. Or dirt. Or mushrooms. And for certain, re-exposing the ancient tobacco to oxygen sets off a rapid decline.
Which reminds me, I have a few tins heading toward that 25 year milestone. Time to pop 'em and smoke 'em.