[sangpal]

Almost every serious lifter is familiar with RPE (rating of perceived exertion) and RIR (reps in reserve). If you reach failure on an exercise, you experience a greater amount of fatigue than if you stopped one rep shy of failure. This allows you to then train the same muscle sooner and you end up building more muscle overall (the muscle gain at RIR 1 & RIR 0 is negligible). But, you need to be able to accurately gauge RIR, which is quite difficult for new lifters.

[sirobg]

Thus in your opinion the advise to train to failure that we see so often isn't as optimal as training with 1-2 RIR? Assuming you train often and that you gauge RIRs accurately most of the time.

[sangpal]

Training to failure once a while is fine, but it is simply not possible to train at a high frequency and go to failure regularly. I personally do not prefer to train to failure more than once every two weeks per muscle group. I advise people that are new to the gym (between 6 months to 2 years of training) to go to failure frequently so that they may accurately gauge what 1 RIR feels like.