I model the dynamic agency relationship underlying prevention. In each period, a principal sets a budget for an agent that has private information about a problem, which the agent can direct to solving the problem or divert into rents. Problems are persistent and rectifiable: they randomly generate observable disasters until enough resources have been committed to solving them. I characterise the principal's equilibrium trade-off between (a) preventing disasters while squandering transfers in informational rents to agents facing trivial problems and (b) limiting transfers and remediating costly disasters that eliminate agents informational advantage and prove the need for action.