A 5ATM rating means the watch has been pressure tested to the equivalent of 50 metres of still water, which in daily terms covers rain, handwashing, showering and swimming in a pool. It is the rating to look for if you want to stop taking the watch off.

The number is not a depth limit. It is a static laboratory pressure test, and moving quickly through water pushes pressure far above what the stated depth suggests. That is why 5ATM comfortably covers swimming lengths but is not a diving or high-speed watersports rating.

Heat and detergent do more damage than immersion. Steam from a hot shower and soap residue both degrade the gaskets over time, so a watch that survives the pool for years can fail in the bathroom.