I've been accusing Mercedes of going to extended oil changes to save money on the so-called free services but I've seen where the Germans are very concerned about ecology and extending the time between oil changes helps reduce the use of resources like oil.

There's a lot of oil in the newer MB engines, the oil filter has been designed for extended changes and MB are now using true synthetic oil of a good viscosity.

However, I live in a very dusty area and I could never go very long before I need new air filters so I'd perform my own maintenance every 12 months.