Oil changes are the cheapest and best thing you can do to prolong engine life. Some new car makers recommend 7500 or even 10,000 mile intervals. While oil has improved dramatically over even the last 25 years, and are probably still capable of doing the job after such a long interval, I would never let any vehicle go that long.
What's an extra $30 or $60 a year compared to the overall cost of vehicle ownership.
