Once in a blue moon.
More Traditional Proverbs:
Be ever vigilant, but never suspiciousTraditional
Speak little and to the purpose.
Traditional
You can't make bricks without straw
Traditional
Mercy to living beings, self restraint, truth, honesty, chastity and contentment, right faith and knowledge, and austerity are but the entourage of morality.
Traditional
Ideas should be clear and chocolate thick.
Traditional
Find a meaningful need and fill it better than anyone else.
Traditional