the game is not worth the candle

The returns from an activity or enterprise do not warrant the time, money or effort required. For example, The office he is running for is so unimportant that the game's not worth the candle. This expression, which began as a translation of a term used by the French essayist Michel de Montaigne in 1580, alludes to gambling by candlelight, which involved the expense of illumination. If the winnings were not sufficient, they did not warrant the expense. Used figuratively, it was a proverb within a century.