What is the origin of the idiom "busman's holiday" and when to use it?

The phrase "busman's holiday" originated in the 19th century and refers to a situation where someone spends their time off doing the same type of work they do for a living. The term "busman" refers to a bus driver, but the phrase can be applied to any profession. It is used to describe a situation where someone spends their leisure time doing the same type of work they do for a living.