Annually, on a fixed date attached to the planning cycle before quotas are set, since quota and territory are the same conversation. Rebuild the opportunity table, recalculate share captured, and check every territory against the capacity ceiling. Between reviews, watch four drift signals: any territory more than 20% outside the target opportunity band, any rep above the capacity ceiling, any territory where share captured has fallen two years running, and any account that has grown past a tier threshold without changing owner. Small annual corrections are absorbed easily, while one large reorganization every five years produces resignations.