No gain is so certain as that which proceeds from the economical use of what you already have. – Proverb

Profits on the exchange are the treasures of goblins. At one time they may be carbuncle stones, then coals, then diamonds, then flint stones, then morning dew, then tears. – Lope de Vega

Take every gain without showing remorse about missed profits, because an eel may escape sooner than you think. – Lope de Vega