I keep all my keys individually. I don't want my Moto Guzzi key or Ducati key with me when on my KTM and vice-versa, I also don't want my car key when on the bikes. I keep my bike keys separate also as the other keys will damage the bike rattling around in the wind and vibrations. Each of my important keys have a different shape fob so I can pull the correct one out my pocket without needing to sift through looking for the right one. Also, if I lose a key, I don't lose all my keys so I can still get on my bike or in my house or in my car. I hate carrying crap around with me off the bike too so means when I go to the pub I just have a door key, again less to lose!