I run a minimum of 10,000 miles between oil changes in my Dodge Cummins. I now have 226,000 miles on it. I also use non-synthetic Rotella T. I'll probably go to hell for breaking all the oil "rules" but I have a secret weapon: I have my oil tested.
I started changing the oil at 4K miles and stretched the interval 1K miles after each test. 12K miles was where the tests started to show borderline oil quality so I rolled it back a bit to around 10K. I decided to use a little science to develop an oil change interval rather than listen to all the oil "experts" out on the net.
Blackstone Labs Works well for me.
Bruce