In the cars I've had over the years servicing has always been an oil change followed by a check up. The thing is, in my opinion 100% of my car mechanical failures in life have either been time related consumables or an issue that was invisible to servicing. Let's face it, I bought a full single merc dealer car freshly serviced...and they missed horrific coking because it didn't show up on a diagnostic or a short run. I don't doubt that merc servicing is 'good' and I'll say without doubt that if you're in the early years of ownership of an expensive investment it may feel imperative (if ironically less of an issue than later). My OCD doesn't like "x years FMSH then specialist" but is my wallet correct?