I'm at 530,000 Km's. It's a loaded down work truck. I changed the oil with 15w40 non synthetic every 10,000 kms'sn but since about 440k, I've been getting synthetic for the same price as non synthetic. I've always used wix filters on it, it gets a new fuel filter every 30k km's. I'm on the original cp3, second set of injectors, 3rd transmission.
A fleet manager was telling me on the big diesels they only change the oil every 35,000 kms.