Research into serious leisure has grown since the 1980s. Despite the popularity of the serious leisure perspective, some embedded concepts remain conceptually underdeveloped, specifically costs and perseverance. Consequently, this paper commences by highlighting the ambiguity surrounding these two concepts. In addition, this paper explores potential overlap between costs and perseverance and the concepts of constraints and constraint negotiation from the broader leisure literature. In doing so, this paper makes a case for enhancing the serious leisure perspective as a theoretical framework by substituting the concepts of costs and perseverance with the concepts of constraints and constraint negotiation. The paper is intended to stimulate dialogue around these concepts that underpin the serious leisure perspective, providing a solid theoretical grounding to guide future inquiry. Future research should focus on the implications of potential substitutive action between these two seemingly parallel, yet conceptually similar, bodies of knowledge within leisure studies.