The responses to this question are really interesting. Some are based on practical objectivity, others are more emotional in tone. Some offer a "we" perspective while others offer a "me" perspective.
I'm more in Defargin's camp when it comes to buying. Last November I could have bought The Briary's entire stock of Stonehaven. It came in the day that I called and Skip was happy to sell me as much as I wanted. I bought two bags and left the rest so that others could enjoy it. Someone else grabbed their entire remaining stock. I found the irony of that hilarious at the time. It also points out why setting purchasing limits has become a necessity. Some folks just don't give a rip about anybody else.
I wouldn't call my cellar large, but if I didn't buy another ounce, I'd be good for a decade at least, and probably considerably more. That said, I'm still buying, but not much, and mostly interesting (to me) stuff that's out of production. I'm not spending hundreds of dollars on ancient vintages likely to be mummy dust or wraiths.
I suspect I'll have fallen off the twig long before I use it all up. I wanted the ability to enjoy some now while letting some age. But I don't buy anything that can't be enjoyed fresh. I'm already aged enough as it is.
There's nothing that I feel inclined to chase as I enjoy a variety of blends and I'm happy that I have no need to stockpile any one particular blend. If I run out of anything, well, that's that, and I can enjoy something else. I smoke a pipe for pleasure, not to turn any aspect of it into a monkey on my back. Having stock also offers me the opportunity to trade, and more importantly, to share with others.
One of my favorite smokes was discontinued when its blender retired and I was really disappointed. But then Russ, who had the recipe book, offered to make it for me and I placed a large enough order to last me quite a long time, provided that I don't keep giving it away. But, of course, I do keep giving it away. The pleasure of sharing is equal to the pleasure of smoking. That's another pleasure of having a cellar.