What is the origin of the idiom "on one's watch" and when to use it?

The idiom "on one's watch" has its origins in naval and military terminology, particularly in the context of guarding or overseeing a specific period of time. A "watch" refers to a specific duty or shift during which a person is responsible for monitoring and ensuring the safety and security of a ship, base, or other area. This phrase is used to imply that someone is responsible for and should be held accountable for what occurs during a specific period of their responsibility or tenure.