I drive about 9K a year, most of it is less than 30 miles at a time. I go by the DIS and use 5-W30 Quaker State Hi Mileage. Vehicle has 166K+. I also keep an eye on the gauges, oil pressure, coolant temp, battery charge, etc. Gauges will tell you more than the DIS will. I run about 100 miles over this time around had it serviced today. Maybe I should have had it done sooner as I blew a brake line on the way home. Good thing I am not a hard driver. I believe is easy breaking and easy starting. I don't need to listen to any straight pipes to kill the gas mileage. Set of brakes will usually run me close to 35K miles. My daughter tell me "Dad, no body drives like that any more". Wanna bet - I do.