yī cùn guāng yīn yī cùn jīn
lit. An interval of time is worth an ounce of gold. (idiom)
fig. free time is to be treasured
yī cùn guāng yīn yī cùn jīn , cùn jīn nán mǎi cùn guāng yīn
An interval of time is worth an ounce of gold, money can't buy you time (common saying); Time is precious and must be treasured.