Rules of Thumb

Now here is an interesting site that lists, of course, rules of thumb that people all over the world have sent in. What's "A Rule of Thumb"? As described by the owner of RulesofThumb.org :

"A rule of thumb is a homemade recipe for making a guess. It is an easy-to-remember guide that falls somewhere between a mathematical formula and a shot in the dark."

Try this: Count the number of times a cricket chirps in 15 seconds, and add 37. No, you didn't just calculate your age in cricket years - you measured the temperature outdoors in degrees Fahrenheit. You just used a rule of thumb.

"A rule of thumb is not always right. It is simply a personal tool for making things work most of the time, under most con­ditions."