what does "to failure" actually mean?

so im currently doing 2 sets of everything and picking a weight where i can onyl do 7-8 reps with it,and training with it until i can do 10-12 reps with that same weight,and then i increase the weight until i can do 7-8 again but with a higher weight,and repeat that.This is called the progressive overlad method buy a guy names troyfitness i believe.

but ive seen other say "2 sets to failure is better" (primarily xinchen,who i completely trust) but if i just do the method i said above isnt it the same thing? bc when you thing abt it when i saw i pick a weight i can only do 7-8 reps,i cant do more than 8,so the 8th is failure...right?


so is this correct? and if not,what is actually "to failure"???


PLEASE HELP