Handle NiCads gently. Although the exteriors may look fine, concussions can damage the sensitive interior of the batteries causing internal shorts which bleed the life out of the batteries as they sit. Whenever possible, recharge NiCad batteries the day before they will be used. Batteries with mild internal shorts drain themselves even faster. You will drain the power out of it before it drains itself.
NiCad memory is a curse primarily of consumer and prosumer gear.
NiCad memory is a condition that occurs when you have used the battery for a short period of time and then recharged it, used it again for a short time, then recharged it, and repeated this process a number of times. Consumer camcorders often have circuits which require 10.5 volts from the 12 volt battery. When the battery goes below this voltage, the mechanism shuts down. If the battery has memory, or one or two cells are weak for some other reason, it is very easy for the voltage to reach the cutoff level causing shutdown. There are also devices that discharge and recharge NiCad batteries to exercise them, reducing the memory effect.