The only way that tobacco will really go bad is if it develops mold. Moldy tobacco is bad tobacco, so you want to protect against that as much as you can. Vacuum sealing will help keep excess moisture out so that the tobacco will not become moldy, but as I mentioned before, mason jars will do pretty much the same thing and as long as you leave a little bit of room in the jar, the tobacco will age properly as well as staying fresh and mold free. As far as tobaccos that will go badly quicker than others, it really depends on preference. Aromatics tend to age less gracefully than other tobaccos because the topping or sauce that gives the aromatic the nice smell can eventually wear off after a lot of aging and can leave the blend bland and boring. Virginia blends offer the best aging benefit as they get sweeter, more mellow, and less harsh the longer they sit. Burleys, I have been told, dont change much as they age, and latakia blends can age differently depending on how much latakia is in the blend. A full on latakia bomb will become more mellow and less smoky after a long time in the tin where as a light latakia blend with more virginias and burleys will mellow out over time. The only real way to know what will age best and what you like to smoke fresh comes from experience. Try as many tobaccos as you can and try them at different stages of aging to see what tastes good and what doesnt taste good.
