Like the best French and Italian wines-- properly stored, sealed in tins or air tight mason jars-- pipe tobacco can not only last for decades but improve. Ten to fifteen years ago, it was a small cult that focused on this fact, and many in the cult were fairly loyally devoted, more often that not, to a dozen or two discontinued blends mainly from storied English producers like Dunhill, Balkan Sobranie, and Sullivan Powell.
Flash forward to today, and you'll find many here routinely "cellar" much of what they buy, laying down their favorites (from some of the brands mentioned in earlier posts) for smoking 1, 3, 5 or ten or more years in the future.
In the old days, there was brisk trade on Ebay (until they changed and began aggressively enforcing rules against the private sale of tobacco). Unfortunately, unlike vintage wine there is not as yet an extensive network of reliable professional sellers, and ideas about what is a "fair market price" can vary wildly.
To take one example-- even with a single, especially popular "classic" that has remained, more or less, in continuous production for close to a century, a fifty gram tin of Dunhill's My Mixture 965 now produced under the Peterson brand name can be found readily for about $14 at most well stocked tobacconists these days.
A tin produced in or shortly before 2018 by the same Denmark-based company (once known as Orlik, later STG) and notwithstanding claims that absolutely nothing about the production of 965 has changed, is to many people more desirable, and even worth a bit more money (although it's not entirely clear if this is because the Dunhill name remained on the label or because a tin has a couple of years of aging).
Go back a few years, to earlier Orlik-era production (say, the early to mid-2010s), and tins regularly fetch $35. And prices can quickly escalate from there. A tin produced during the late "Murray's" era (blended in Ireland) can regularly sell in a matter of seconds for almost $100.
Go back further to the period prior to 1980-1, when Dunhill blended and packaged 965 itself in England, and the price doubles or triples. Indeed, an asking price for a tin without a speck of rust can be $500+--although how many tins actually trade hands at such a figure is really anybody's guess.
As for any of us that still may have some 965 "cellared" from the 1970s or before, or who luck out, as occasionally happens, stumbling on a stash at a neighborhood thrift store? Do we open it and smoke it? On a special occasion? This will routinely spark a pretty lively debate. But, at least to my mind--not unlike wine, books, old masters paintings, retired Ferrari racing cars, old fountain pens, contemporary art, and of course vintage pipes (and unlike Beluga caviar), pipe tobacco is now--for better or worse--a "collectible."