I buy 5100 by the pound; and I'm currently working on a freshly opened pint jar that's been aging for almost two years. This blend is considered to be ideal for aging (cellaring) in that it undergoes one of the greatest transformations of any tobacco. If you can't cellar bulk tobacco try McCranie's Red Ribbon. There are two crop vintages that I know of: 1983 and, I think, 2000.
Just moments ago I was the beneficiary of a rapturous confluence of mood, chemistry, circumstance, pipe and tobacco, which elevated a mundane bowlful of C&D's Haunted Bookshop to the sublime experience for which we pipe smokers live. I wish you all the same epicurean delight from your pipes.