Heck, maybe I should start looking for a new engine. Mine has lost about a half quart of oil per tank (+/-350 miles, so that would be a quart every 600-700 miles) since I bought it with 35,000 miles on it. It's got about 80,000 on it now but there's been no change in oil consumption.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless