There is enough information around regarding aging, cellaring, and storing technique in this forum and other sites; as well as plenty of reliable accounts of success with doing so that it should be enought to relieve any unease one might have with regards to the soundness of the investment.
If you can stumble upon a tin that has been sitting on a back shelf in a B&M for a few years and it still smokes just as good (or better) as a new tin, it's reasonable to assume that the same would hold true for a tin stored on a bookshelf in your home for a few years.
If you wanna know what aged tobacco tastes like it's not hard to come by, either via internet vendor, lucky score at a B&M, box pass, secret santa, trade or even just plain old brotherly generosity. I've only been a pipe smoker for a short while, but I've tried several tobaccos that were much older than the year or two that I have actually been smoking a pipe. I've got enough stored to last me several times that span and plans for more.
It seems (to me anyway) that it's really a matter of whether you want to pay some now, or pay more later and a matter of whether or not you like what age can do to a blend.
Edit: with regards to the OP, Irish Flake is not a blend I would consider cellaring for the benefits of age, based on the information I have gathered. If you really want to know what aged Irish Flake is like, check pipestuds site frequently or just simply buy an extra tin next time and set it aside for a decade or two :lol: