Probably best advice I've heard is to check the oil at every fill-up, that way you're guaranteed to be looking every week or two, though it sounds like that may have not fixed your problem. Also good to be in the habit of looking under your VX every time you walk up to it to make sure nothing's leaking. If you lost 5 quarts in 3 weeks you would think that it had to puddle somewhere along the way.

Please don't feel like I'm lecturing; even though I know all those things to do, I rarely remember to do them myself.