To recover effectively between sets, resting for two to six minutes can be beneficial for hypertrophy and strength gains.

For strength training, a regimen of three to five compound exercises for three to five repetitions per set, with three to five minutes of rest, performed three to five times a week is effective. This approach allows for significant strength gains without excessive soreness.

A good muscular endurance training protocol involves performing three to five sets of 12 to 100 repetitions, focusing on exercises like pushups and pull-ups to build the ability to perform work repeatedly over time, with concentric movements and 30 to 180 seconds of rest in between.

To determine if you're doing the right amount of volume, consider how many sessions you have per muscle group in a week. If you're training your chest twice a week and feel fully recovered before your next session, you can increase the number of sets you do.

If you're doing something like nine sets for biceps, that's totally cool, but you just have to train them less frequently to allow for recovery. If you're doing 15 working sets for just your biceps in one session, the literature suggests that's not optimal because your last sets may not provide effective stimulus due to fatigue.

Most people should aim for 5 to 15 sets of resistance exercise per week per muscle group to offset declines in muscle strength.

Training to failure can lead to greater muscle growth but also increases fatigue significantly, so it's important to balance intensity and recovery. Going from some number of reps in reserve all the way to failure in a single mesocycle is a good practice for many, but not required; you can go two or three reps in reserve as long as you do enough sets to achieve close to ideal hypertrophy outcomes.

If you can't match or beat your previous performance in two consecutive sessions, it indicates that your cumulative fatigue is too high, and it's time to either deload or adjust your training volume to allow for recovery.

To improve strength, you should perform anywhere from two to 20 sets per week, with five sets being sufficient to maintain muscle mass.