Burn not your candle at both ends at once.

Meaning: Depleting your resources simultaneously from opposite directions ensures swift exhaustion and waste.

Origin: Candles were costly, and lighting one at both ends burned it twice as fast. The image came into English from French — Randle Cotgrave's French-English dictionary of 1611 records brusler la chandelle par les deux bouts — originally for squandering money; it later came to mean exhausting yourself by working early and staying up late. Edna St. Vincent Millay's poem "First Fig" (1920) made a boast of it: "My candle burns at both ends; / It will not last the night."