Not really a problem for me either

From Brad DeLong’s Semi-Daily Journal: A Weblog:

And then there was the sign I saw on a door in the twisty maze of little passages all alike scores of feet below the classrooms of Berkeley’s College of Chemistry:

     PLEASE HELP US TO BETTER SERVE YOU BY
     PROVIDING AT LEAST 24 HOURS’ NOTICE (48
     IF POSSIBLE) OF YOUR LIQUID HELIUM
     REQUIREMENTS.

I don’t know about you, but I am generally able to anticipate my liquid helium requirements more than 72 hours in advance…