Which lapel is the year membership pin placed on?

The year membership pin is traditionally placed on the left lapel of a jacket. This placement is significant as it aligns with established protocols for pins and insignia, which often denote honor or achievement. The left side is generally reserved for items of importance, such as medals or emblems, which symbolize a person's affiliations or accomplishments. Thus, wearing the membership pin on the left lapel demonstrates pride in the organization and the year of membership, making it a visible and celebrated aspect of a member's identity.