Mine gets serviced roughly every 3 months and the local dealer to my work place was doing a full service everytime and it was costing me alot.
I changed to another dealer abit further away and they said you only need an oil change as it had a full servcie 2.5months ago.
I have asked BMW to confirm what items are on a 6k miles and which ones are based on time, i.e. 12 months change. But still waiting for them to get back to me.
It works out expencive when you are having 4 to 5 services a year.