As seen in this FS/T thread there is a nifty app called coconutBattery that gives one the stats on batteries and their capacity and charge cycles. So far my iBook has been blessed with a good battery: 3037mAh of stock 4200mAh (72%) on the original 45month old battery and 196 loadcycles. As far a LiON packs go, this one is doing really well. I can push it up to 3-3.5hrs of time if I drop the brightness to min and set the CPU for minumum speed (approx 400MHz for the 600MHz CPU), and a bit more if I wasn't running the AirPort card the whole time. So, my nearly 4 year old iBook can run on WiFi and play on the 'net for a solid 3 hours on it's original battery pack, sweet. If it was doing any worse I'd consider a new pack, but for now it's just not worth it. Anybody else got some long-life stats to report?