Thanks for asking. I linked it on purpose to wikipedia from where I quote:

The meaning is sometimes used less colloquially as: "Meanwhile, the irreplaceable time escapes", expressing concern that one's limited time is being consumed by something which may have little intrinsic substance or importance at that moment.

Tempus fugit is a succint admonition to focus on what is really important as opposed to what is merely salient. Focus on the not urgent but important things(quadrant 2 in the covey matrix).

http://en.wikipedia.org/wiki/File:MerrillCoveyMatrix.png

I thought it was a good quote, although I'm not sure LWers need to know it. (On the other hand, one might think the same thing of curing aging or helping cryonics, but Eliezer's essay on his dead brother still got a substantial reaction.)

Do you like this one better?

"Buy not what you want, but what you have need of; what you do not want is dear at a farthing."

--Cato the Elder; Epistles (94) as quoted by Seneca