IWC Schaffhausen 5454 Mode D'emploi page 18

Note
Leather is a natural and permeable material. Make sure, therefore, that the
high-quality leather strap does not come into contact with water, oily sub-
stances, solvents, cleaning agents or cosmetic products. This way you can
prevent discoloration and premature ageing of the material.
How often should my watch be serviced?
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.
Effective from February 2012.
Technical specifications subject to change.