What must a New Prince do once he has become Prince?

In chapter 6 Machiavelli argues that a new prince should be good as long as that goodness is politically useful. It is impossible for a prince to be perfect and to exercise all virtues; therefore, he should not worry about guarding against vices that will not cost him his state. He should avoid those vices that lead to the kind of disgrace that could precipitate a fall from power, but while he should try to avoid those vices that are not as damaging, if he cannot prevent them, he is allowed to indulge them.