I've been using NiCads for the last 46 years and have NEVER been able to make one get a memory. That is an old tale that has been around since some of the early satalites where they erouneously attributed their problems to memory which could never be duplicated in the laboratory no matter how hard they tried. NiCads do have a limited life although it is twice as good an NiMh has. There is a gradual degredation with age and with number of cycles of use so it does pay to cycle them once or twice a year just to see if you are nearing the end of their life cycle. This is more important if you do a lot of fast charging (greater than .1c) as fast charging does degrade them faster than the .1C charge rate does.