['neutral']
He has lived by his wits as the saying goes. 
הוא חי על פי שכלו כפי שאומרים. 
He has shown that he has been living by his wits, as the saying states.
הוא הראה שהוא חי לפי שכל הישר שלו, כפי שאומר הפתגם. 