AS mentioned elsewhere there are certain truisms which seem to hold good. Some are good general life laws and some could be exclusive only to carpet cleaners.
Here are some to kick off with.
You will always run out of clean water with only 2 square yards of carpet left to rinse/extract.
THe chance of a call-back is directly proportional to the further distance that the custy lives away from you.
The waste tank will trip the ball valve when you only have two square yards of carpet left to rinse/extract.
More general ones include the first law of motoring which states that the first fly to hit a clean windscreen will always land directly in front of the driver's eyes.
Or Murphy's Law which states that "anything that can go wrong will go wrong".
Mind you I've heard that there is an amendment to this law which states that "Murphy was an optimist"
