A: John was promoted to be the regional manager last week.

B: Through many years’ hard work, he has finally earned his stripes.

Note: The idiom means to “prove that one is deserving of a particular position or designation.” “Stripes” refer to the narrow stripes of braid embroidered on the shoulders of army men to distinguish their rank or experience. The higher the rank or experience, the more stripes one gets to wear. This idiom is often used in situations where one has earned a promotion through his or her hard work.