From what I’ve seen, most IWC automatic watches generally need a full service around every 4–6 years depending on usage, accuracy, and how often the watch is exposed to water, shocks, or magnetism. IWC itself says service intervals depend on wear and lifestyle rather than a fixed schedule. Official service turnaround is usually quoted around 4 weeks, though some owners report anything from 2 weeks to a few months depending on the model and parts availability. (IWC Schaffhausen)
In terms of cost, owner experiences seem to range widely simple movement service can be a few hundred dollars, while complicated models or vintage pieces can go well above $1,000. The good news is that long-term reliability on modern IWC movements is generally very solid if serviced properly. After-sales support seems mixed though: many people report excellent and fast service, while others mention long delays or frustrating repair experiences.