full rep ranges, unless 1- your hurt. 2-you are working on a specific range (example: getting the bar off you chest for bench press) 3- or your a ***** trying to impress only your self

as for the amount of reps 3 - 20 is ok depending on what you would like to do compaired to your goals...
strength = lower reps
putting on size = getting the muscle pumped
cut = diet