This is definitely one question that a personal fitness trainer and bodybuilding coach hears very often. As we grow we learn that that working harder will bring in more results. Unfortunately this is not at all true in bodybuilding. If we do too many sets and do not give the muscle enough time to recover we will be faced with a stop in performance. Our muscles might even become smaller if this continues. Unfortunately it is very difficult to know when we reach such a point in our workout because different factors will influence it. In any case, there are some signs that are linked with overworking your muscles. This includes loss of appetite, force loss, blood pressure being too high, body temperature rising unnaturally, loss of willing to workout or sleeping disorders.
It is very hard to tell you how many sets to perform. A lot of amateur bodybuilders have learned that Arnold Schwarzenegger used to do around 20 sets for each muscle group. Unfortunately not everyone can do this. In fact, there are different cases of people that do not grow if they do more than 2 or 3 exercises for each body group and leave a recovery time of around 1 to 2 weeks before working out the same group. Although they will not make it in professional bodybuilding, they can still build a lot of muscle mass. In fact, you should always know that everyone can build different amounts of muscle mass.
You can only learn how many sets to perform for each exercise and muscle group by learning how to understand and listen to your body. It will let you know exactly how much it can take. You can only properly learn how to do this by trying out different workouts and see exactly what works best. Also, supplements and rest play a crucial role in bodybuilding for everybody. Never neglect this and know that proper supplementation can aid you in doing more sets and basically building more muscle mass before you get to that point of overtraining. Always choose only the best supplements, rest properly and maintain complete seriousness when working out. By doing this you will gain the best possible results at all times.