How Often Should I Change My Oil?

As some of you probably already know, I've got a bit of interest in motor oil. I'm not sure exactly how it started, but it led to me being involved with the bobistheoilguy.com message board back in 2002. From that site I've learned a lot! But the one thing I've noticed when I'm on other message boards is that most people change their oil far too often! They say that they like to change it every 3000 miles because it's "cheap insurance". I'm here to tell you that this way of thinking is very outdated! With today's motor oil being a lot better in terms of engine cleanliness and viscosity retention, and today's modern fuel injection systems allowing more precise control of fuel management, there really is no need to follow the old 3000 mile rule anymore. In the old days a lot more fuel ended up getting into the oil, and that would degrade it a lot faster. Combine that with oils that didn't keep the engine as clean, and it meant you needed to change it more often to keep the level of protection at it's best. So why do so many people still subscribe to the belief that they need to change their oil every 3000 miles? I think it's a combination of two things: one is the fact that oil change places keep advertising that it needs to be done this often (and of course they are going to say this, they want your money!) And the second reason is because people say "my father changed his oil every 3000 miles and his engines never wore out". That right there makes sense, but you get to a point of diminishing returns, because a guy changing his oil every 1000 miles isn't going to get 6x more engine life out of the guy changing his oil every 6000 miles. It simply doesn't work that way! Every situation is going to be slightly different, which is where used oil analysis can help out a lot in terms of pinpointing a more reasonable interval for your engine and your driving habits. But even if you don't do used oil analysis, you can still safely extend your oil change intervals without fear that it's going to cause your engine to die a sudden death! From what I've observed on used oil analysis reports you can safely go 5000 miles between changes in most engines using a good quality name brand conventional oil. When it comes to synthetic oils, you can go even longer!