Different degrees of failure. Momentary, positive, negative and a few versions in the grey area. Absolute failure: when the weight overcome the muscles ability to move in a positive (raising) direction or resist in a negative (lowering) direction. Even holding a weight in a static position can be near impossible after taxing a muscle to it's limits.
I can say, from witnessing and good personal sources, that most of the truly successful large and powerful men will stop 1 or 2 reps away from any form of failure. Less can be more in this regard. The CNS and it's ability to recover from a present workout and be geared for the next workout , is key to size & strength. The prime word being "Recovery". These guy's understand all of this and apply it to their workouts. Even guy's, floating in a sea of 'roids or whatever else, tend to back off of going the failure route.
Only exception might be a 1 or 2 set max, in a higher rep range (like breathing squats, DL's, squat cleans, etc) or a program like Mike Mentzer's. Including the positive and negative phase in the same exercise/workout. All these really attacks the CNS, but for a shorter duration with the 1 or 2 sets max.
All this is a personal choice. If people want to do failure every workout, than fine,. But you may be short changing yourself in the long run, if progressive gains, from workout to workout, are the goals. If feeling a sense of adventure, try stopping 1 or 2 reps before your usual point of failure, and see how the body reacts after 2 weeks or so. Good Luck.