Samkvæmt leit um þetta,,,,

"Longer than the car usually...

You should only replace the chain if you're already in there to replace the cam sprockets or Vanos (usually becuase of noise/rattle associated with excess wear) - or perhaps as a preventative measure if the head is already off for some reason.

On a properly maintained M52 - this should really never have to be done as part of regular maintenance. "