I have always had Ni-Cads, since my first Sears Craftsman 12 professional drill/driver bought back in the late 1980's. I changed it out years ago in 2005 for a Bosch 18 volt Ni-Cad.
I used to do renovations, which I found very hard on cordless tool batteries. I have learned over the years that any battery does not like getting over hot. So the key thing to remember when using any cordless power tool, as soon as the battery starts getting warm or hot, put it aside and change out the battery.
Also at least once every 3 months, I place my batteries — 12 of them — one at a time in a flash light that I have from my kits, turn it on and drain the battery, then recharge it. I also make it a point never to leave a battery on the charger more than the time it's charged.
I have about 13 to 15 cordless Bosch tools plus about 12 batteries, and numerous chargers for them. I have the Bosch 12V Li-ion for work on air craft. I can say that they are much more sensitive to heat, and have had 1 to 2 batteries fail in only a 2 year period, while my Ni-Cads are still going strong.
But what ever some one decides, remember keep the batteries from getting hot, and you shall be fine.