I too cycle my new NI-Cd batteries to break them in.

When finishing the initial cycling I record the mah and the date on the individual battery using a permanent marker. In doing this I can see how the battery progresses through its usage. I consider a battery bad when it reaches 70% of its rated potential. Batteries need maintenance meaning that they need to be kept charged and cycled on a regular schedule. Allowing a battery to sit and pretty much totally discharge for extended periods of time diminishes the life of the battery.