What is the origin of the idiom "dos and don'ts" and when to use it?

The origin of the idiom "dos and don'ts" can be traced back to the early 20th century, where it emerged as a concise way to express a set of guidelines or rules. The phrase is derived from the use of "dos" and "don'ts" as shorthand for "things to do" and "things not to do." It is commonly employed in areas such as etiquette, safety protocols, job training, educational settings, and general life advice.