Water-resistance is not a permanent quality. Watch seals age at different rates, depending on how the watch is worn and what it is used for. In addition, sealing elements are attacked by sweat and acids, and they deteriorate over time. If a watch is exposed to big changes of temperature — for example, if the wearer takes a sunbath and then jumps into the water — condensation may form inside the case. Saltwater also causes increased corrosion. That’s why a watch should be rinsed in freshwater after a dip in the ocean. We basically recommend having the seals and the water-resistance of a watch checked once a year. We perform this service for our customers free of charge.