Thanks for that.
But if shutting off is required, Apple's recent wireless keyboard and wireless magic mouse are currently looking like significantly underdeveloped inventions.
If, to get Apple's predicted four months use for those two peripherals, one has to shut them down every time one walks away from the computer to shop or go play tennis (I always shut down the computer at night), then some of the pluses of those two peripherals are lost. (I know: Apple makes it easy to shut them down via a menu bar icon. But still -- this frequent need for shut down is not, clearly, the way of a happy customer world.)
Moreover, how come my keyboard batteries are looking good but not my magic mouse batteries? I shut down neither, and I'd say I use the keyboard much more than the mouse. If shut down of the two is needed, how come the keyboard is doing okay but not the magic mouse?
Apple has a nice thing going with the wireless keyboard and the magic mouse, but there is still some techie applicational research yet to be done to make Apple's four months prediction for use a veridical prediction. And for many (not me), the wireless keyboard is as much of a disaster as the magic mouse -- regarding the unwanted need for short term battery renewal. Have you googled these problems?