I was recently talking to a motor trimmer and he said the two model cars he hated dealing with were newer Mercedes Benz and BMW. The quality of the plastic degrades over time as it is meant to be biodegradable or made from recycled materials and our sun/heat does it no favours. The biggest problem for him was this increasingly brittle plastic has clips built into the interior trim panels rather than separate clips like most Land Rovers, and they too often break. So, inevitably, exit the original panel and enter a newly bought one. He now warns BMW and MB owners of the possible problems ahead of time.
