IWC Aquatimer is the dive watch that IWC makes, and it is underrated. Forget Submariners. Luxury is an internal bezel, a clean dial, a robust case. It is the watch for people who know IWC does more than pilots.
The question of when to service a watch is a quiet anxiety for every owner. Forget waiting for failure and ignoring the signs. Luxury is a five-year interval, a trusted watchmaker, a movement cleaned before it complains. It is preventative care for a mechanical soul.