Three levels of failure. Keeping this simple because it's really a complex subject. A point of any level of failure can affect not only a selected muscle group, but the whole body also. Which, in turn, affects the Central Nervous System (CNS). The CNS rely's of full recovery to function normally. The CNS is the key to muscle response and future potential of muscle growth and strength...when it is, in fact, allowed to function normally with rest and recovery.
1) Momentary failure
2) Temporary failure
3) Complete failure
General rule among Olympic lifters, Power Lifters and advanced BB'er is to avoid reaching a point of failure in training. Stopping 1 or 2 reps away, on any set, from reaching even a point of momentary failure. Lifters will usually test themselves for improvement every 3 weeks or so, with max weights, per lift, held to 1 to 3 reps. BB's may tend to do this also, though not needed for encouraging muscle growth.
This is where many BB'ers make the mistake of exhausting their CNS and not allowing enough recovery time, from workout to workout, with too many exercises, sets and workout days per week. Successful and experienced BB'ers tend to find that less is always more, with shorter workout and shying away from any point of failure. If your the one in a million gifted with superior genes, you may get away from any form of volume training......many have in the past. Or shooting up in the cheeks 2 times a day, you may thrive on any extreme method. If an average BB'er, spinning his wheels with not much in noticeable results in months, or even years, might suggest avoiding the point of failure and reducing the workouts and work load per week.
Good Luck