Agriculture; the ability to produce surplus amounts of food allowed some members of society to be free to do "other things" such as metal working, trade, and science. It also led to lawyers so it does have some drawbacks.
I assume you are talking about storing it long term unopenned. It will be fine; there is an inner plastic seal. When you do open it the lid seals fairly well, I have a tub about a year old and it has been fine to smoke.
At this point my tobacco purchases are at a maintenance level; I wait for a sale and restock what I've smoked. Sometimes I pick up something new to see if it can replace a cellar blend that is no longer made.