There a comes a time with a laptop when it is necessary to buy a new battery. I've had my rev. B 12'' Powerbook for almost two years now and the battery is nearly shot. Only gives me one hour of light duty battery life. Videos or anything like that completely drain the battery in under a minute. In fact, if I let the laptop sleep long enough that battery goes completely dead and the clock would come back up as 1969. I entertained the idea of picking up a new, $129 battery, for a couple months now. Last night I finally went out and did it. When I put it in the first thing I checked the was the battery capacity. About This Mac --> More Info --> Power --> Full Charge Capacity. Now, only my old battery this number was low, under 2000. On the new one, out of the box it read 4400. I was happy. I wondered if I should even bother to calibrate it. I did. Now the full charge capacity reads 4547, it went up. Very nice. Always remember to calibrate your battery, at least once a month.