Synthetic Oil is really good stuff. I change mine every 5000 miles, regardless of how good it looks (I plan on keeping my Renegade around for a while. And there is no substitute for good and regular maintenance).
Several tests have been done on the waste of good oils, meaning, that we (in most cases) change our oils on a regular basis rather than as required by testing of the oil. We grew up on the mindset that regular (organic) oil should be changed every 3000 miles or 1 year, which ever comes first. But in reality, the oil isn't contaminated or broken down enough to require a change.
I guess that I am a creature of habit. I would rather change my oil (synthetic) every 5k then pay to get it tested to see if an oil change is actually required.