Pharaoh Amasis knew how to divide time between duty and pleasure

' Archers, Amasis replied, string their bows when they wish to shoot, and unstring them after use. A bow kept always strung would break, and so be useless when it was needed. It is the same with a man; anyone who was always serious, and never allowed himself a fair share of relaxation and amusement, would suddenly go off his head, or get a stroke. It is because I know this that I divide my time between duty and pleasure. '

Herodotus - Histories (II, 173)