based on the reactions of checkers and those who have been checked
And yes, I advise the Chronicler not to be stingy and use Night Defense. 5 nights is a long time, and the game might end by then (although it's unlikely given the current situation).
BUT! If you've already used a check this night, then DON'T go on the second night. All your Night Defenses are better spent against already identified negatives than used randomly.