I change the oil/filter in all my vehicles every 3k miles. However, I have a friend who bought a new Chevy Astro van and had the oil changed about three times over ten years. He would brag about his lack of care and how it never broke down. Not only is he bad on maintenance he never washes or cleans the interior of his vehicle. Six months after he bought it the van looked worse than a New York City taxi. This guy can trash a vehicle faster than anybody I've met.