iwc Da Vinci Chronograph Mode D'emploi page 27

How often should my watch be serviced?
24 | 25
The optimal service cycle for your IWC timepiece is exclusive to your
watch and unique lifestyle. The necessary interval between services will
be determined by your individual wearing habits; frequency of wear,
your environment/s, and the intensity of physical activity you engage in.
Your fine mechanical timepiece is an extension of yourself and will run
well for as long and smoothly as it is treated. Therefore, we simply
recommend you to continue wearing your watch for as long as pleases
you and to only entrust it for a service if you notice a deviation from the
regular performance, function or timekeeping. It will then be our
pleasure to reinstate the premium performance with the suitable service.
Status May 2007.
Technical specifications subject to change.