Ideally, mechanical watches should be inspected and cleaned every 3 to 5 years to ensure correct operation. The moving parts of quartz watches also need to be inspected when the battery is replaced; even the tiniest speck of dust can prevent the watch from running as it should.
The battery should be replaced as soon as the watch stops or when the power-reserve indicates the end of its lifetime. This is a very fast, routine operation. Maintenance of water-resistant watches may be less frequent. However, water-resistant seals must be replaced if the watch is opened. Water-resistance can be checked by a specialist reseller.
It should be borne in mind that frequent exposure of the watch to chemicals or seawater for example can also damage straps, bracelets and plated cases. The same is true of perfumes and certain cosmetics when applied directly. At all events, a timepiece manufactured from appropriate materials and fitted with a suitable strap or bracelet will help to prevent any inconvenience.