If you’re taking a hot shower or a sauna, it is recommended to remove your watch even when they have high water resistance. Most military watches have a water-tested rating for up to 100 meters. Some even have as deep as 300 meters but none of these make a difference to the risk that heat poses. Extreme heat naturally expands the metal parts in your watch. It leads to the possibility of creating small openings that can do damage inside. The most common result of water damaging the watch is the formation of misting in the crystals. Increasing amounts of water damage may also seriously damage the watch’s movement.