Might suggest (for what it's worth) at least 1 or 2 reps away from complete failure, on every set. Pl'ers and experienced BB'ers understand this.
Not over taxing the CNS (Central Nervous System) can allows almost complete recovery which is the key to steady progress in gaining strength and muscle size. Going to failure every workout can whack out the body at times.
If your a juicer, than they may or may not help recovery time. Any drug will not always work the same on each individual. Some get amazing results, others notable improvement..and still .others..nothing at all in improvement. Drugs always seem to work best on the genetic gifted, who would be stronger and more muscular naturally, even if never touching a weigh in their life. I've met a few.
In some protocols, testing the muscle strength will require hitting a point of failure to check lifting progress. Maxing out in other words. Usually every third week, depending on the coach. Works fine for Olympic and PL'ers.
Good Luck.