If serviced by a Leitz dealer it's on record with the company. When I accidentally cracked the view finder glass window, I sent my M3 to a UK Leitz accredited repair shop, I was given an estimate and told they would have to also service the camera. Expensive.
I was surprised to be informed the final charge was way lower than the estimate, as records showed my camera had been serviced just before I bought it (2 or 3 years earlier). That's integrity, and also honesty.
Ian