We keep hearing how good so many conventional are these days. I have been changing oil in my cars for 40 odd years. Oils have gotten better and better. I hear about cars that even if you use synthetics the manufacturer still wants the oil changed sooner than many synthetics claim you can run it. I think I have such a car. Nissan wants me to change the oil at 3750 miles and does not specify conventional or synthetic. The spec is use API SN oil. Just change it at 3750 miles if driven in the conditions that we do drive it in. Lots of stop and go in the city. Well I don't put any expensive synthetics in it. I have, but realized I can get the same bang for my buck using high quality conventional or blends. Right now it has Chevron supreme 5w30.