"Time is money" is an aphorism that is claimed to have originated[1] in "Advice to a Young Tradesman", an essay by Benjamin Franklin that appeared in George Fisher’s 1748 book, The American Instructor: or Young Man’s Best Companion, in which Franklin wrote, "Remember that time is money."[2]
However, the phrase was already in print in 1719 in the Whig newspaper The Free-Thinker: "In vain did his Wife inculcate to him, That Time is Money ..."[3]
The saying is intended to convey the monetary cost of laziness, by pointing out that when one is paid for the amount of time one spends working, minimizing non-working time also minimizes the amount of money that is lost to other pursuits.[4]
Outside of a purely pecuniary context, similar sentiments about time spent have been expressed since time immemorial, such as the famous essay De Brevitate Vitae by Seneca the Younger.