My 99 E320 wagon FSS counts down at around 12K miles (19K km), which is usually around 12 months of driving for me.
However, I do an inbetween oil and filter change at 6 mo or 6K miles (usually alternate Mobil 1 0W40 and/or Q-State European Formula 5W40). Not sure if this extends the life of the engine or other components, but I can't wait 12 mo to change the oil.
Note that I'm still running with the original harmonic balancer with 100K miles (160K km).

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2012 ML350 Bluetec 4-matic
1999 E320 4-matic Estate


"A ship in harbour is safe, but thats not what ships are built for". - John A. Shedd

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