Science of pump sets

[Machmood]

Instead of making Another thread I will just ask here. As great as DC is, It's really brainwashed me in terms of I refuse to not take any sets to failure. Or at the very least I feel like I've missed out if I don't. Could you briefly describe why you chose loading sets in the higher tiers to not take that first set to failure. Also what Benefit does taking an ISO movement to failure between loading sets. Won't that just fatigue you and take away from your big movement ??