My beloved Prius has 25,000 miles on it. I have changed the oil every 5,000 miles until this point. I do a mix of driving but my daily commute is only 6 miles each way. I also do a fair amount of highway driving. I don't know if this would qualify for extreme or severe driving conditions. I last got an oil change in May and now have 5,000 miles since then. I'm toying with now changing my oil every 10,000, but am worried about the effect this may have on my engine. I also have a 3,000 round trip planned for October and would hate to leave with 6,000 miles on the oil. A part of me wants to just go to 10,000 for short term budget reasons and not wasting money. Thoughts on this matter are greatly appreciated.