I remember first reading about the myth of muscle confusion. It is the idea that you have to constantly change your routine to keep your body guessing and to make continuous gains. This is just complete bullshit.
To get stronger in the gym, you must lift heavy things, do the correct exercises with proper form, eat a complete diet, and give your body proper rest. Changing your exercises with high frequency is not needed. In fact, it can even slow down your progress.
When I train clients whose goals are to build muscle and strength, I always incorporate some type of squat, deadlift, bench press, overhead press, and row in the program. Doing these exercises will bring your strength to new heights and your muscles to where you want them.
By constantly changing your routine, you are unable to evaluate your progress. It is easy to know you are getting stronger if you more weight is being put on the bar. How can you know if you are getting stronger by doing different exercises and reps every other week? You simply can’t, which leads to working your ass off with minimal (if any) progress.