How many times do you take the key out of the chuck and put it down only to have to go looking for it as you change bits? I used to keep the key in a metal box in a drawer beneath the drill press but it took just as much time to open the box place the key then open the drawer pick it up again and use it.
I found an inexpensive solution that works terrifically.
I took a rare earth magnet (sample pack obtained from Lee Valley Tools) and epoxied it on to the side of the drill press. Even if I am not looking I can pick up the key, use it and put it back since the magnet is strong enough to draw it in from 1/2" away. Since doing that I have not misplaced the key again.