Question

I've seen lots of cordless nicad and nimh batteries get very short life because they were overcharged to death because of cordless phone chargers typically don't shut off at the end. So yes in my experiance it would be lots better to take the phone off the charger when the battery is fully charged. And I do want to point out the "memory" is largely a myth because people call any sort of capacity reduction or any failure "memory". It is like a blanket statement.

Here are some things to ponder, because I know what goes on in nicad and nimh batteries. When a battery is rechaged, crystal growth occurs on the plates. When you discharge a battery, the crystals go away. Normally, those crystals are very small and don't pose a problem. When you discharge batteries only a small amount then charge the already mostly full battery, those crystals are not broken down completey so the new crystals grow on top of the old one and get a little larger. After many (say 20-30) times, those crystals get too large and they insulate the plates from the separator, which makes it harder to get the electricity out of your batteries. You can restore the affected battery by discharging it completely and recharging it about 2 - 3 times in a row. Those crystals are broken down and battery will be restored.

Overcharging also encourages crystal growth. I am not entirely sure yet, but I suspect that during the super long overchaging causes the crystals to grow so large that they poke a hole in the separator, effectivly ruining the battery.

This is new technology, baterries nowadays are not what they used to be and charge discharge rules no longer apply, unless GE (made in China) is installing old type batteries which I highly doubt. It used to be that way but not anymore, leave the handset on the cradle it was designed that way.