Water damage prevention is a tricky subject to tackle, however we will try to explain as best we can. As a watch ages, the aging seals (gaskets) become less reliable. They are usually some type of rubber or plastic that becomes brittle with age. These seals must be replaced and tested in order for the watch to be protected as it was when new. When a watch leaks the damage will begin immediately and progress until the watch is dried out. Most watches currently sold are sealed at the factory and may or may not, be marked “water resistant”. The maker knows it will last longer without problems if it is sealed. After the manufacturer guarantee has expired, you are on your own.
How can my watch get water if i do not swim?
When a watch becomes wet for any reason it usually cools the watch. The air inside contracts, if there is a leak, water that is clinging to leaking watch is drawn inside. The watch does not need to be submerged in order to draw in water. Sometime all it takes is a splash from washing hands, a rain shower, or a spilled drink. When the water does get in the like is usually to small to let the water back out so it condenses on the inside of the watch.
Why does water cause damage?
Watches should be inspected for leaks periodically and the seals replaced when old and/or unreliable. Sealed watches (water resistant) with a small leak cannot dried themselves out. The moisture is trapped inside until the case is opened. A tiny amount of water can go unnoticed and remain trapped in the watch for months causing great damage. But it does not take months for a watch with water in it to have enough damage to cause a costly repair. The damage can start in hours of the water getting inside and does not stop till the water is removed. The watch should be resealed after the removal of the water to prevent leaking.
But my watches have not need it before?
Some watches are made without seals (costume watches or older dress watches) this may have been yours. Not being sealed allows for air circulation and the trapped moisture can escape if put in a warm place for a while. For this reason water resistant watches with a small leak are more susceptible to water damage than a non-sealed watch. Any moisture inside a watch should be removed immediately to prevent further damage.