Your mileage may vary
(Standard disclaimer attached to EPA mileage ratings by American car manufacturers) A ritual warning often found in Unix freeware distributions and elsewhere. Translates roughly as "Hey, I tried to write this portably, but who *knows* what'll happen on your system?"
Nearby terms:
Yourdon/Demarco « Yourdon, Inc. « Yourdon methodology « Your mileage may vary » youtube.com » YouTube, Inc. » Yow!