Ars Longa, Vita Brevis:
I had always assumed that this means something like "art can endure even after an artist's death," and others seem to take the same view. (I had considered and discarded "having a large arse is bad for your life expectancy.")
But my father reported to me that the original meaning of the quote -- apparently by Hippocrates, in Seneca's translation -- is something like "There's much to know, and little time to learn it," with "ars" meaning (more or less) skill. What's more, that appears to be at least a common modern meaning, rather than just a historical meaning long abandoned by modern users. And it's always dangerous to use phrases that have multiple meanings, unless the multiplicity of meaning is part of your goal.