I bought a 05 Corolla a in 2017. The car has 80,000 miles on it and was previously owned by a priest who has become to elderly to drive. The church practically gave me the car. The official Toyota guide book says change oil every 5,000 miles or 6 months. I've been changing it every 6 months with a orange Fram and Valvoline MaxLife Synthetic Blend 5w30. The thing is, I only put only about 6,000 miles on it per year. Can I extend the oil change to 9 months? I do a lot 80% stop and go big urban city driving though. I was thinking about going to a 5 30 Quacker State full synthetic. I don't do rebates and not too sure about the Supertech oil brand. Any advice, thanks...........