 When these two conditions are met, Mill believes, agents should for the most part follow these principles automatically and without recourse to the utilitarian first principle. However, they should periodically step back and review, as best they can, whether the principle continues to satisfy conditions (1) and (2). Also, they should set aside these secondary principles and make direct appeal to the principle of utility in unusual cases in which it is especially clear that the effects of adhering to the principle would be substantially suboptimal and in cases in which secondary principles, each of which has a utilitarian justification, conflict (II 19, 24–25).