when i first played cod for the first time i used 5 then 7 then 10, i always use the highest now, everybody who reads this should learn to use the max sensitivity (14 on black ops 2) at the moment, i always see retards going down in zombies because they can't turn around fast enough, if you have the highest sensitivity and know how to use it you will be a good zombies player and it helps heaps in multiplayer too, i don't understand how anyone could use lower than 10 it's way to slow and by the time you turn to where you need to turn to you're already dead