Ford has been studying the question of when to suggest oil changes, and they've hit upon 7,500 miles for 2007 and newer cars. Not only are modern oils better, modern engines are also better. You don't have carburetors metering poorly on winter mornings, tolerances are a lot tighter, and operating temperatures are typically a little hotter, helping to cook off the junk that accumulates in the oil. Some manufacturers use a sensor to monitor the health of the oil and light a service lamp when it calculates change is required. Ford contends that its customers prefer a set amount of miles between changes. The automaker also cites the environmental benefits that come from less waste oil, monetary savings, as well as extensive tests as positive aspects of the new recommendation. I'm convinced that the only reason to suggest changing the oil at 3,000 miles in a modern car is to sell more oil. Perhaps an air-cooled Porsche would stress dino juice more, and could sensibly require changes at 3K, but you can stretch to drain intervals that would make your father gasp and clutch his chest by running modern oils in your modern engine. Of course, your driving pattern has a lot to do with it, as well. If you're in town for short hops, you'll require a shorter drain interval than the guy running Mobil 1 for his highway commute and changing the oil at 25 kilomile intervals (raising my hand).