Hello everyone. I had a full synthetic Amsoil put into my motor some time back. It is rated to last 20,000 mi but I have always been a little hesitate to go that length of time for the oil to be changed (filter is to be changed out at 10,000). So, I was wondering everyone's thoughts on this? I'm not too informed when it comes to oil life. I have had the same oil in my car since 118,000 and am at 126,000 right now. My gut is telling me that I might be pushing my luck with this oil and run the risk of sludge build up. So, thoughts everyone? Should I get changed ASAP or wait?