A good way to kill most NiCad batteries early is to park them on a dumb charger when not in use. I think you will usually see some mention in the manual to disconnect the appliance from the charger after it has reached full nominal charge.
Of course, there were generations of Dustbuster-style vacuums with wall-mountable docks that had integral charging contacts, supplied by ‘vampire’ wall warts that were always on…
Look up the physics behind the ‘memory effect’ to get some idea of the best charge and discharge strategy for NiCads. The pravda years ago was that when you observed the rapid exhaustion problem starting, you deep-cycled the thing a few times – let it run until completely dead, then charged it up fully. To my knowledge there is no comparable issue of dendrites in lithium rechargeables that would not produce some kind of battery fire…
I have still not quite figured out what is best for various eras of what used to be Li-ion batteries; my understanding (possibly defective) is that the ‘better’ appliances include charging-management ‘chips’ that regulate the charging when the device is continuously plugged in.