Определение и Значение "worth {one's} salt"

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

The idiom "worth one's salt" has its roots in ancient history. In various cultures, salt was once a valuable commodity and was even used as a form of currency or payment for work, hence the word "salary" being derived from "salt." The phrase reflects the idea that a person's value or worth is determined by their competence, contribution, or ability to fulfill their role, much like the importance of salt in preserving and enhancing food. This expression is used to commend or acknowledge someone's competence, skill, or ability in their profession, task, or role. It implies that the person is truly deserving of their position or reputation due to their capabilities.