I used to do mine on 3750, but now I do 3000 miles because every 6 I get a free tire rotation, and its easy to remember its ever 2 oil changes. No one on here like the fact I use Plain ol' Valvoline 5w-30 either, I know, since we've had that discussion before, but its worked fine without a single drip for the last 180,000 miles, so I don't plan on wasting money on synthetic or anything else that costs twice as much and does very little on a 3000 mile change schedule, if it actually does anything at all. I'm not sure how many of you want to compare 180,000 mile engines using synthetic, or high mileage, or anything else with mine...