I personally enjoy doing a set of 8. When I say I reach a new PR(bench or squat or DL) I usually just mean that I can finally do 8 reps of it. I could probably do pretty damn heavy weights if I did 1 rep max but I wonder: is it just a vanity thing like “look how much I can lift for 1 single rep” or is it actually something to help me increase my mass? Or would a 5 rep increase mass more?