Final answer:
Waterproof watches have a maximum depth to which they can safely be taken while swimming due to the increased water pressure at greater depths.
Step-by-step explanation:
Waterproof watches have a maximum depth to which they can safely be taken while swimming because of the water pressure at greater depths. The deeper you go underwater, the higher the pressure becomes. This increased pressure can cause the watch's seals to fail and allow water to enter the watch, damaging its internal components. To prevent this, waterproof watches are designed to have a certain level of water resistance and are tested to ensure they can withstand the pressure at specific depths.