The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as in poetry.
At a restaurant do you order what you know is great, or do you try something new? Do you make what you know will sell or try something new? Do you keep dating new folks or try to commit to someone you already met? The optimal balance for exploring new things vs exploiting them once found is: 1/3. Spend 1/3 of your time on exploring and 2/3 time on deepening. It is harder to devote time to exploring as you age because it seems unproductive, but aim for 1/3.