Legal careers can take many directions, and lawyers have different ultimate career goals. Traditionally, though, most attorneys in private practice at law firms have aspired to partnership. This makes sense given the hierarchical structure of most law firms and the "up or out" system that firms often employ, under which junior attorneys must progress annually through increasing levels of responsibility and roles before being promoted to partner or asked to leave the firm. There are exceptions to this path, with some attorneys taking permanent counsel or other nonpartner-track attorney positions or specialized support roles. However, there is often not a business case for retaining a more expensive nonpartner senior attorney when classes of junior associates continue to arrive and progress.