over tightening can lead to pre-mature failure of the cable ends. along with using a screw driver or like to try and pry open the end clamp to much, when removing cable to fix vehicle or tractor. that metal of the ends is rather "brittle / weak" stuff. it bends a little bit, but if ya over do it. the cracks happen. and the cracks just feed a bunch more corrosion.
i have used pepsi / coca cola in a squeeze (out of town) and corrosion on battery cable not getting good contact, a little soda to fuze off the corrosion and off i went. next day new end, but 2 buck soda vs 100 plus buck towing charge....and not able to get to work... i hate soda due to it leaves sticky mess behind but *shrugs*
on tractors, riding lawn mowers, etc... stuff that may not get used for a couple weeks or longer at a time, "quick disconnect" battery ends are installed. much easier to deal with, vs dealing with a possible dead battery. granted some equipment is a pain in rear. due to no actual space around the battery for quick disconnect ends, and leaves ya hunting for different types of quick disconnect ends. at one time, tractor was in a location were cats and other varmints would be running around area and needed a trickle charger to keep battery up. the regular alligator clips most battery chargers / trickle chargers have, would of fallen off if something looked at them wrong. i just remove the alligator clips for quick disconnects on the charger. and all was good.
i have used nails, screws, little bit of wire before, to place between battery clamp end and battery post. due to not a snug fit (cable was easily sliding off). most of the time i have had to go get new cable end. due to i goofed up and got end out of shape / open the clamp up to far or someone else did. to keep a good connection, and reduce corrosion that would quickly show up.