If you're doing a lot of short runs it's a very good idea to change oil between CBS. I would change oil every 12 months or 12k km. BMW Australia is trying to convince Munich to change the CBS for Australian cars because of the harshness of the weather here.
If you plan to keep the car for long then do it.
2007 E92 6MT - Silverstone II with /// Performance Exhaust with ACM Test Pipes and BPM Sport Stage II Dev-Tune - Proper engine warm up, 12-monthly oil change, Castrol TWS 10w-60
2014 F15 X5 3.0d