Larry,
I was hoping you'd chime in
What happened at 380,000 miles? Are you on the original chain or how much was it stretched when it was changed?
The point here is that adhering to a change interval that's best for your engine can save maintenance in the long run - like changing the timing chain. For MY driving habits and engine, changing synthetic oil every 6500-9500 miles works. I've tested it with oil analysis and engine condition confirms it. For others, mineral oil changes will work better. In my opinion, changing oil at the "right time" - either synthetic or mineral - is very important. More important than what kind of oil you use.
Regards,