Like most everyone else on this site, we all know that oils are good well beyond 3000 miles. But let me make this point and tell me where I'm miskaken. In engine wear tests (as read in How to choose a motor oil for your car and truck)most wear is caused by particles at sizes of 10-15 microns and below. Many oil filters are not good and capturing particles in the very small range. (We are assuming most people are not using a bypass oil filter) So if many filters are not capturing particles extremely small in sizes that are causing most of the wear, then the only way to get rid of these is change the oil, right? With everyone pushing for longer OCI's arn'these wear particles just getting more and more causing more and more wear, even though the oil may be good. Where am I wrong on this? Naturally UOA can tell you if you are getting abnormal wear, but I'm talking about getting the least wear possible within reason.