Total volume is important. But so is intensity both defined as percentage of your maximum and the rate of perceived exertion aka RPE.
The aforesaid is simple enough I think, so I'll explain RPE.
Like you could say on a 1-10 scale, a 7 is something with 4-6 reps in the tank. An 8 is 2-3 reps in the tank. A 9 is 1 rep in the tank and a 10 is an all out effort.
So you could ramp up using increments of 10% to an all out set of 8-10 and that could be a good training response.
You could also keep doings sets of 5 reps with that same weight until say you feel like you couldn't get more than 1 more rep on that set and that too could be a good training response.
Some people do better with one approach. Some do better with the other. For some, it won't matter. To complicate things even more, for a single individual one approach will work better for a while then the other approach will work better.
Clear as mud?