I've always changed our N55 equipped vehicles at 7,500 and let the dealer do it at the 15k mark. Waste of money? Maybe. But I enjoy the quality time I get to spend with the vehicle and it's not really that much when I do the change myself. I enjoy it actually.
We are about to have our first N55 equipped vehicle, an X3, go past 40k miles. Thus I'll be doing the oil changes on my own dime from here on out. Anyone know what a dealer would charge just to reset the oil life parameter? I can see them wanting something crazy. Wish there was a way to manually do the reset myself.