Old folks often say 'an inch of gold cannot buy an inch of time' to remind us not to waste our youth.
Tips
history
Almost always quoted as the second half of a couplet: 一寸光阴一寸金，寸金难买寸光阴 ('an inch of time is an inch of gold; an inch of gold cannot buy an inch of time'). The first half goes back to the Tang poet Wang Zhenbai 王贞白 (875–958) in 《白鹿洞》, and the longer pairing became a stock saying in Ming-Qing primers like 《增广贤文》.
usage
Said when urging someone (often a student or young person) not to waste time, or when lamenting one's own lost time. The metaphor uses 寸 (cùn, a Chinese inch) as a unit for both gold and the sunlit shadow on a sundial.
