Forget the lifetime BS story. Older BMWs had a much more rigorous maintenance protocol (when it was the owner's nickel). Changing lubricating fluids and various filters on high performance engines is cheap insurance on early failure. My schedule for '04 X5 3.0i as per Mike Miller's old school treatise:

oil/filter - 5K
air filter & AWD transfer case fluid - 30K
power steering fluid - 30K
AT fluid & filter - 50K
spark plugs & fuel filter - 60K

Much of this is DIY (thanks to this forum!), except where a lift is essential. She runs like a top at 80K miles. Only major work was CV joints last summer. Very happy with the car.