Read: I beat the hell out of my car

I used to have an 89 Plymouth Acclaim Turbo that I changed the oil about that often. After 1500-1800 miles, I could feel a big difference in performance. My friend is a Mopar performance freak, and said because of the high temps it wouldn't be a bad idea to change it that often, especially if the performance was dropping noticably.

What's $6 a month on oil & filter?

Anyway, I'd be really wary of that car man. Keep looking, let some other sucker bite on this one.