BMW used to say it was a 15, 20, 30 and 40K service on various components... like back when they wanted people to think their vehicles lasted forever. I know of 2 300,000 mile E30s with original automatic trans.
Now it is lifetime or 100,000 miles. BMW has changed to what I deem a recycle me car. 100K and it is time for a new BMW. If you follow that schedule you are looking at a much longer lasting vehicle. Diff fluid, coolant flushes, trans fluid etc all needs to be changed at regular intervals. BMWs will push 15K or more on oil changes. No thanks