I am not quite sure, Last time (roughly 7 months ago) I did a major service, changed the breaks etc. According to the sticker that the mechanic has put on, I am due for another round in another 2000 Ks. I do not think anything will be required other than the routine oil, air filter, etc change.
Having said that Originally when i bought the car (2 years ago) the car was leaking oil and the mechanic supposedly fixed it (said something about Vanos) and then it was still leaking so i went back and this time he said there was a crack line in some pipe and he fixed that a swell. Long story short, I have been to the mechanics a few times for the oil leak but it is still leaking or burning oil somehow. So i have given up and i just add a liter of oil on top every few months. I don't know if that is normal or not but I have ran out of money to spend on the car. I would have changed the oil myself but i hear you need special tools.