I usually don't rebuy, I've only rebuyed 1 or 2 times, but I don't like to rebuy, I think it will depend on how that person's game is, for example if you don't get anything right during the whole tournament I don't see the need for you to invest But in a tournament where nothing is going well, also if the tournament is quite advanced and the blinds are very high, I don't see the need to risk either.