I change the oil frequently enough, that if it did go through a bit of oil - it gets topped off with a fresh new supply before it could become an issue.
Lots of pavement miles puts you in the realm of checking it like you would a street bike - less often. In the dirt my oil gets looked at virtually every time I take it out.... if I were commuting on it, that inspection would probably get lax and normal consumption would seem to be exaggerated.
For peace of mind, if I were riding that many pavement miles....I would just change the oil often, and the filter every other oil change. Then you could rest a bit easier.