I have to agree with Small Town Raptor. Unless I encounter severe driving conditions I change oil at 7,500 mile intervals. You may ask how many miles I put on vehicles without having any problems. I put 136,000 miles on a Tundra a few years ago and it ran like a sewing machine when I traded it. I put 132,000 miles on a 2006 Chevy Impala SS and never had a problem with it. I put 60K miles on a 2013 EcoBoost FX4 SCREW before trading it and it ran like it was new. I put 56K on a 2013 6.7 diesel and it ran like it was new. A friend of mine was asked by some (change every 3K miles) acquaintancies) how often he changed oil and his reply was, "I haven't ever changed it. I just add a quart about every 15K miles. Asked how many miles he had on his car and he replied, "130K miles." I borrowed his car one day and it run like it was new. IMHO, as Small Town said, you are wasting your money. Oil has come a long, long way from what it used to be. BTW, I have researched most oils on the market below AMSOIL and have found one that I am extremely happy with. It is PENNZOIL ULTRA PLATINUM FULL SYNTHETIC. You can order it in 5 qt. containers from Walmart online and have it delivered to your door for free. Good pricing too.