Back in the bad old days, conventional wisdom said everyone had to change their engine oil every 3,000 miles (4,828 kilometers) (or until their dad bawled them out for leaving that crud in the engine for more than three months.) Then engine technologies and oil formulations improved, and that guideline was raised to 5,000 miles (8,047 kilometers), then 10,000 miles (16,093 kilometers).
Miles are so old-school, yo.
All the cool kids now have sensors that can tell how filthy your oil is. Cars also monitor your driving habits and make oil change suggestions accordingly. Drive low and slow? You can squeeze out a few more miles. Treat every red light like the drag race in "Better Off Dead?" You're going to need to change that oil often. And your overlord ... er, car will tell you about it. And if that car is a BMW with its fancy teleservice system, it'll rat you out to the dealer by calling in the filthy state of your oil.