I’m old school when it comes to training. A lot of guys do 1-2 warmups and then go right into their max/heavy set.
How I train is I do a warm-up set and then add a few pounds and shoot for my target reps. Then add a bit more weight and repeat. Then add more again and repeat. I work my way up adding weight as I go and continue to shoot for the same amount of reps. My last set will be the set that is the hardest or that I fall short in reps. So that can be anywhere between 4-6 sets.