We change our oil and go in for scheduled maintenance every 7500 miles or six months, whichever comes first. We use a synthetic blend and have never had a problem. Most people have their oil changed way too frequently. Dealerships and quick lube places have them believing they still need to change it every 3000-5000 miles, or every three months, like it was recommended years ago. I think a lot of people just don't take the time to read over their car's manual and maintenance guide, and rely rather on what the mechanic tells them for regular maintenance, which of course if they had their way would have you coming in every 1,000 miles.