I like 20 reps on my squats but I'm an athlete and I explode through the top, bar speed is the goal. Just all depend on your goals of what you are doing, if you aren't a BB or PL no need to be strict at all. I have bad knees to begin with, but I probably on hit parallel on occasion just by dumb luck. still have 30 inch legs (mid thigh) and I got speed. So just for all the other guys out there don't worry so much just lift and reach your goals.