I've posted this before but will do it again. I changed my oil 3 times up to 18k using dino oil then switched to Amsoil, I use a the bypass filter setup. I change my full flow filter every 8 k, and my bypass filter every 24k. I changed my oil at 88k because of a malfunction in my air box. The oil analysis caught that I had a high silicon level. The chemistry on the oil was ok to continue using but I dumped it because of the dirt in the oil. I am up to 120k on the truck and have not changed the oil since. Like amsoilman I also have gone well over 100k on the same oil. If you change your filters and keep up with your oil analysis, there is no need to change your oil that often. If you aren't comfortable doing that, fine, but it does work. I've gone over 500,000 miles in my last two Dodge trucks to this point with 0 engine problems. Works for me.