First, buy in small quantities with any blend you haven't tried, and for all new pipe smokers, since your tastes will change. Buying large quantities, even of blends you enjoy, may put you off them because you can always have all you want. I have rescued a few tins where the Lat went flat or something else was disappointing, by adding another condiment or blend. With small quantities, this usually works out fine, and gives you a layperson's short course in mixing if not blending. If it is a blend you think others really do enjoy, you can take it to a pipe shop where there's smoking or a pipe club and let others share it while you smoke something you like better. Don't take something that may be generally disliked or others may follow your example. I'd give any jarred blends at least a year before trying them again; they may improve, or your tastes may change, or both. When buying tobacco, make sure you understand if it is aromatic or non-aromatic, and in aromatic what the flavorings are. Know the constituent tobaccos, the cut, and the base versus the condiment tobaccos. Know if you like Virginia, Latakia, Perique, burley, Oriental, and so on. I'd give any blend three or more bowls before you decide you don't like it; blends can unfold once you learn them.