It really bugs the heck out of me how this same question keeps getting asked and badly answered all the time. I have just a simple question. How important is your car to you? If it isn't very important then go ahead and listen to the owners manual and all the BS opinions people have about changing the oil on your car.
If your car is important to you (as it is to me) then error on the side of caution. How expensive is it really to change the oil and filter on your car? I change it myself and I spend about $20 all included. So I think I can afford to be a big spender and take a few minutes out every few months and change the oil on my car even if it may not need it. Will it break my wallet? NO. Will it waste my time? NO, because at the same time I check out everything else and make sure that my car is running perfectly. Its called maintenance folks.
Take this from a person who has never ever blown out a motor or transmission in all the years and models of cars that I have owned. I keep my cars for the long haul so I prefer to baby them.
I don't know if its laziness or cheapness but I can't fathom for the life of me why anyone who has a nice car (it's a mustang folks not a civic) would really want to stretch out how many miles you get out of that oil change. I rather have a car that is in pristine condition than one that is junk under the hood. I know 20 years from now I will still have mine, while I know many of yours will get traded or junked.