To cellar or not to cellar, that is the question. There is no correct answer.
Let's start with cellaring as a hedge against increased costs. That's probably the best argument for cellaring there is, closely followed by hedging against the disappearance of favorite blends. A lot of blends are going off the market in a couple of years due to FDA regulations. The quality of the leaf and the manner in which it is harvested and processed appears to be lowering due to the loss of price supports. Farmers are turning to more profitable crops.
So why not just pile in and buy a ton of the stuff?
No reason not to if you know that you really love what you're buying. But if you're fairly new at this you may find yourself with a pile of tobacco you may later find that don't like. You might be able to trade for other tobaccos or sell off some of it, so there's that, but you still may not get your money back.
I bought only what I really enjoyed smoking, and have enjoyed smoking for years. Even so, my tastes shift. I have tobaccos that I currently don't feel like smoking that were favorites just a few years ago.
Or you might be one of these guys with 400 lbs in the closet who suddenly croaks out on the squash court. Ooops. The widow and orphans are stuck with a pile of weed and it goes in the dumpster if you haven't left instructions on how to dispose of it.
So think about your needs before you start spending.
Onto the benefits of aging. Aging doesn't improve tobaccos. That's bullshit spin. Tobaccos change while aging. Whether that change represents an improvement is up to the taste of the individual smoker. There are blends that I like with a few years on them and others that I really prefer fresh. Years ago, blends went through extensive aging before being released for sale. Nowadays many blends don't get that long gestation period. But most blenders would say that their product is ready to be consumed when released. A couple of years ago Robert Germain stated that aging their product was pointless as it's ready to be consumed upon release. Of course, they're a very old school blender.
As has been said before, Virginias become sweeter, though not all of them, over the years and they can go for 50-60 years before they peak and fade. Yes Virginia, tobaccos, like everything else on the planet, have a shelf life. Besides the sweetening, their other flavors can become a bit fuller and rounder. I'm saying can, because not every Virginia changes equally with aging. Some of that may have to do with the conditions under which the tobacco is being stored.
Burley seems to be the aging champion. I've smoked blends nearly 100 years old when the only clear note left in that zombie vomit was the burley. It can get a little bit sweeter with a more pronounced nut like flavor. It's just not going to exhibit as much of a change as do Virginias.
The various Orientals seem to age very well for decades, with their flavors becoming a little more pronounced over time.
Latakias fade, or to put it in more politically correct terms, they "soften". That smokiness is a process, not the base character of the leaf, so it fades over time. But that's not necessarily a bad thing, as many smokers prefer the "softened" flavors of aged Latakia. My experience with them is that they can hold up just fine for the first decade or so before they exhibit any noticeable fading. Up to 20+ years that fading continues on a gentle path and by 35+ years that smoky flavor is nearly or completely gone.
And there are always exceptions because a major part of the cellaring process are the conditions under which the tobacco is stored. Ideally it's stored in a cool dark dry environment. If it isn't, aging may be somewhat less than optimal.
So the other part about cellaring is protecting your investment. Modern tins are fine for short to medium term, as in up to 7 years, maybe 10. But tins, especially the square and rectangular pressure sealed tins, fail over time. This can be a concern if you've mortgaged the house to buy a 400 year supply of tobacco. It's probably because they're not really completely sealed and are leaking from the get go. So you need to seal up the tins so that they don't eventually dry out when the seal fails, if you're going to keep your tobacco in the tin for more than 7 years. A lot of people heat seal their tins in heavy duty food storage grade Mylar. Others jar their tobacco in mason jars.
I've smoked a fair amount of vintage tobacco. Some of it has been marvelous. Some of it has turned to crap. Buying vintage tins on the secondary market is something of a gamble. As long as you know that you're taking a risk you have no complaint. Personally I've decided not to buy any more vintage tins of tobacco, unless they're being sold at discount. I'll be happy to pay $3 - $4 for a 1970's tin of 759.
If you know what you like to smoke, by all means buy some extra to put away. It's nice to be able to smoke what you want when you want it. If you're still exploring, don't buy out of panic, take some time to find out what you like.