Like mentioned before oil analysis is your friend. I put about 5k a year on my 06 now and it gets changed just once annually . I did have the oil analyzed for a few years and I kept stretching intervals when it was my daily driver and I could easily go past 6k. I think there are tons of variables when it comes to this question so you need to get a baseline and go from there. My truck has 145k on it now and every time I have to tear into the engine (self induced) it looks great. I think most oils are sufficient now nowadays but have ran Rotella t6 in this truck for the past 10 years.