John, their not morons, just being overly cautious. We were so used to changing oil at 3k, that we still feel we have to. Back in the day when all we had was petroleum oil, you had to drop oil at no longer than 3,500. Reason was oil started to break down, and was losing its ability to protect. Full synthetics will go out to 15k, but you still have dirty oil pumping through your motor. I changed my oil/filter last weekend with a tick above 6k. I run Mobil 1 5w30, with a premium fram filter. I know I could go way further, but I do a lot of low mileage stop and go driving. The reason I run fram is my 4x4 is a pain to get filter off, the fram has the rough grippy stuff at the end. 3 years, and 26,000 miles, no issues.
Sent from my N9131 using Tapatalk