Every 2 years from build date brake oil change, not reg date as its when the oil was put in the car.
18K estimated oil change + oil filter+ micro filter (unsure if this should have been changed)
36K estimated should be oil change oil filter /spark plugs,+micro filter+ air filter.
year 4 and 5 MOT insurance included. (year 3 is included but I think is standard with BMW BUT you do it before wty runs out).
Oil top ups for 5 years. (I think I have used 2L in 2 years in the 10 plate)
Then it gets a bit tight assuming the estimated milage
54K estimated oil change + oil filter + microfilter NOTE WILL BE just out of the 50K unsure if you could pop it in and get it done, I think there is a milage band of 3K.
Next brake oil will be 6 years so that will also be out.
Above is initial miles and then depends how you drive it.
So its not just the oil you need to look at
My last 10 plate had a premature oil change (it went in for brake oil and ended up with a full service!!) at 15K. last key data reading at 30K it was showing 9K remaining that makes 23K per oil change.
For me I do 12K miles a year and like to keep the car 6 months after its 3 birthday. My new one was built in December 12, pre regestered in Jan and I purchased it 2 weeks ago with 28 miles on the clock. I was able to purchase the service inclusive and I jumped at it, as the 1st brake oil and 1st oil service combined is over that. When I come to sell I will be pushing for a few pounds back. If I keep it for a few months more then I will need the big service and another brake oil change which will be free.
I may need to do this as the new z4 will be out and the used market will be stupidly high like in 09 so ill ride it out for a year while it settles
If you intend to px before 20k miles then dont bother. even after 2 years the brake oil change is only around £150.