So there you are pumping out 7-10 sets of 20 reps.
You are sweating and feeling great.
You move onto the next exercise for the same muscle group but it is a different machine or exercise so you go ahead and dot he same thing.
2 hours later your exhausted, sweaty and you leave the gym feeling great.
The next week you notice you did not add any muscle weight to your body.
Maybe you shrug it off, it has only been a week right? So a month goes by and nothing changes but you know if you stick with it you will see results.
I hate to tell you this but you are only half right.
If your ultimate goal is to have a muscle building workout then you need a routine to match your goal.
If you are doing more than 5 sets then you should be increasing the weight.
If you are doing more then 10 reps then you should be increasing the weight.
Sure it is hard, but what do you expect? Doing the same thing every week, now that IS madness.
Lastly do not do more than one exercise per muscle group.
Why? Well it makes sense if you think about it, how many times do you really think you need to stimulate the same muscle? One exercise, if done right with the proper weight and correct number of sets and reps is more than enough to get it growing.
Any more just makes it easier for you to get injured.
So save yourself some time and your muscle some potential injury and do only one exercise per muscle group.