Questions like this are worthless unless you see someone's FORM.
I see guys at my gym throw 3-4 plates on a side, then proceed to drop down like 6 inches - and they call that a squat. What BS.
To me, if your thighs do not at LEAST go parallel to the floor, you have not gone low enough.
But most guys get SO focussed on how much IRON is on the bar (instead of doing the movement correctly) that they do half-assed squats. Same with bench presses, curls, cable rows, etc. Its sad.
I do full sets of squats with only 275 on the bar. Not a lot - right? But I know guys that will put like 400-500 on the bar and could never do my 275 and drop as low as I do.
Plus, I have been blessed with large legs, I dont work them too much becuase if I do, they get oput of proportion to the rest of me.
Anyway, its not just about "how much iron". Form and the speed of the movement have a tremendous effect.