NEVER CASTLE IF U HAVE NO CORNER PAWNS. the point of castling is mainly that your king is relatively protected by the pawns as the only threat to the king is either through a bishop/queen or for a frontal attack, as the pawns provide sacrificial protection and the two rooks make ure kingside row almost invulverable.
personally i avoid castling unless it is absolutely vital cuz it tells ure opponent that there is a weakness in ure defense which he may not have spotted. i have played with people who castle at the first chance possible and have beaten them 98% of the time.