This perspective paper makes a brief conceptual review of continuity and argues that relationship continuity is the most controversial type. Plentiful evidence of association with better satisfaction and outcomes urgently needs to be supplemented by studies of causation.The scope of these has been outlined in this paper. Evidence strongly suggests that patients generally want more relationship continuity than they are getting and that relationship continuity is linked with better patient and staff satisfaction. This is reason enough to justify improving relationship continuity for patients.