10/21   To extend the lifetime of your cell phone battery, is it better
        to leave them plugged in whenever possible, or to charge them only
        when absolutely necessary?
        \_ All the battery chatter I've heard so far is to not have it
           plugged in constantly but also not to let it drain completely.
        \_ For NiCd batterys, you are supposed to charge it fully when you
           charge it, and use it to empty before you charge it again.
           Otherwise it dies quickly.  That's called "memory effect" or
           something.  For NiMH and Li-ion batteries, supposedly you don't need
           to do that, but I do it anyway.
           \_ I've started seeing more manufacturer service advice suggesting
              to keep Li-ion on charge whenever possible, as the life is
              related to discharge cycle count and charge/discharge temperature
              (which goes up w/ current).  The main reason they aren't saying
              this outright is that customers would interpret this as being
              inconvenient.