Everyone needs an Egg Timer (sometimes more than one). They are handy for dozen's of uses besides just timing an egg. Do you want to get 20 minutes of shut eye without having to figure out what time to set an alarm clock (assuming you have one handy)? Do you want to limit some of your phone calls to 30 or 40 minutes? An Egg Timer is perfect for those situations and many more.
I especially like the new electronic Egg Timer. They are smaller than a mechanical timer, meaning that you can slip one in your pocket or purse. They are quiet, so no annoying clicking (keeping you from getting the most out of your 20 minute nap). They don't have a spring that will wear out, so they keep time the same ten years from now as they do today.
Electronic Egg Timers also use so little juice that the batteries last the better part of forever.