On Saturday, I plan to change my car's oil for the first time (first time I will have changed oil that is). THe previous owner used a synthetic blend oil from Mobil 1. He said he changed it every 7500 miles. I think he just went by the bottle of the synthetic blend oil, it says "Guaranteed for 7500 miles". So I decided to spend the 6 bucks a quart and got fully synthetic. It's twice the cost, but my car doesn't take much oil, so I figured I might as well.
I am told fully synthetic motor oil will last even longer. What is a fair estimate for how long I can keep this oil in my engine? Assume normal driving conditions, not extreme dust or anything.