I mean that’s such a loaded question. I wrote this a few years back as someone who never really trains to failure, so it’s all about choosing the right loading. Number of sets is unrelated to intensity. You could realistically have a workout with only 3 work sets that leaves you completely gassed for days, or you could do 30 sets submax focusing on acceleration and leave feeling completely refreshed and ready to train the next day.
Right now most of the more advanced advice on here is heavy on the high intensity approach, and I wanted to highlight an alternative as someone who’s been moderately successful training submax almost my entire career. When I’ve tried high intensity approaches, it fucks up my sleep, my physique depletes like a pancake, my cortisol sky rockets and my T levels tank. It’s not for everyone.