I keep seeing folks on here talking about building up their oil supplies at the house. Why have a large supply ( more than is needed for the next O.C. ) at the house that will be several years old by the time you use it? Wouldn't you want to be using the latest oil formulations in your vehicles instead of oil bought years ago? I don't keep more than an O.C. worth around. Just don't want to take up too much space with stuff I won't use for years. What is the thinking behind a LARGE supply at the house? Just wondering.