Fitness & wellness — spec it like a studio bills and books

Boutique studios, gyms, coaches, on-demand brands. Members on recurring plans, classes with finite capacity, retention won or lost on attendance. A builder who models this as "events + tickets" ships something no studio owner will run their business on — because the hard parts are billing and waitlists, not the calendar. This skill is the domain briefing so the spec is right before code starts.

1. Domain vocabulary (know these or look naive)