There is a lot of pseudo-broscience out there claiming that pushing weights past the point of failure is the best way to train for gains.
But you can guarantee that you'd never see any athletes with sport-specific goals doing this themselves.
It's all about context (and specificity)
To promote muscle growth, there is an intensity threshold that must be reached before weights even become effective: basically, results won't come from lifting weights that are far too light; nor will muscle growth won't come from lifting moderately heavy weights but for too few reps.
All this is vastly different to completely failing reps due to form or fatigue.
Studies that have previously suggested lifting weights until failure can promote muscle growth were more focussed on very young adults who were performing relatively simple exercises as opposed to complex moves.
Simple and complex moves
There is an easy way to differentiate what a simple and what a complex exercise is: exercises that require multiple joints, a high degree of skill in execution and a large amount of mental focus are considered complex (eg. Olympic lifting, deadlifts, back squats); whereas an exercise which is stabilised by a machine for instance and only involves one joint and basic movement mechanics can be considered a simple exercise (eg. bicep curl machine, pec fly machine, leg extensions).
When performing the more complex exercises, you should be stopping short of failure by 2 or 3 reps or as soon as your form breaks down. Athletes who perform these complex movements almost never fail their lifts and have de-loading periods programmed into their training cycles.
Only when performing "simple" exercises should training to failure be considered. There is far lower central nervous system (CNS) demand and less reliance on flawless form in these low-skill exercises. But the message remains that if achieving failure on these might promote muscle gain. (And that is a large emphasis on the word might - there is just no guarantee that the end result is worth the discomfort.)
Train smarter, not harder
Want a better alternative?
Don't aim to do one huge set to failure on your next muscle group. Instead, reduce the total amount of reps by roughly 25 per cent. Then add one or two more total sets to your workout with this new rep range.
This way you will have achieved more total volume and will have a shorter recovery time for your next workout, enabling you to train harder and more effectively. Which ultimately, leads to more muscle growth. Guaranteed.
Your body isn't bulletproof
Seriously though, your body isn't a machine.
It can be far more beneficial to split one incredibly hard workout into two moderately hard workouts with the same total volume (or even slightly higher). After a hard workout, your body needs time to recover, this is known as residual fatigue.
Complex and demanding exercises require a large amount of CNS drive. Its recovery relies on external factors such as adequate sleep, rest, appropriate calories and macronutrients and solid hormone levels.
Training also releases a hormone known as cortisol. Too much of it in your system is a bad thing, it will lead to fat gain, poor sleep and recovery and stop the one thing you are trying to do in the first place: build muscle.
Accumulate too many of these stressors and you will end up with lower libido, a compromised immune system, adrenal fatigue, debilitating DOMS (Delayed Onset Muscle Soreness), a lack of energy, and a higher chance of sustaining an injury.
Regulate, recover, repeat
During your training consider utilising a method called RPE (Rating of Perceived Exertion). Give yourself a sliding scale of numbers from one to 10, with one being a stroll in the park and 10 being total failure in strength, energy or form.
Try to never reach over an eight and that will give your body the best chance to recover from your workouts, for your form to be safe and effective, and give you the ability to train again without having to take days off to recover. That also works for the other end of the scale so stay away from one to three otherwise you run the risk of wasting your time.
Focus on your form and technique and this will help you target the muscles you are actually trying to train, rather than recruiting a whole bunch of unwanted ones in the process.
Take slightly longer rest periods when necessary and rather than always slapping more weight on the bar, consider the tempo of your reps. By slowing the speed down or adding pauses to the exercise, you will recruit more muscle fibres and unlock the next level to your training.