Thanks for the advice. I've been on many forums over the years and have read many people's blackstone reports. Without doing one myself (and I probably never will) I've changed to 10,000 mi oil changes with full synthetic Mobil1. All of my vehicles are high mileage rigs and I have no reason to believe there is anything that will fail due to a problem with engine oil. As a matter of fact I've never had an engine fail and I've been driving and wrenching my own cars for 40 years. It's always wear parts like brakes, shocks, struts, sensors, etc.