What is your goal? Your goals could be cardio? Muscle Building? Strength building? Fat loss? Weight loss? Kill time? Get away from your kids? Doing any old work out checks a few of these boxes but each goal has it's own "optimal" or nearly optimal workouts. In general, for muscle building, I would not change up my workout very often. And do higher reps. The Subject is Strength training, so is your goal to get stronger? If so, I would keep the weight high and the reps low. Also for strength...you don't do chest, back, or shoulders or is shoulders part of arms? I can't imagine a quality workout for strength training without doing chest, back, or shoulders. Look at Strong Lifts. There aren't even arms in there because doing chest, back, and shoulders takes care of arms. Anyway, it looks like you do total body work outs. If you feel the need to "change" your workout, I would make two workouts. Workout A and Workout B. Week 1 Mon=A, Wed=B, Fri=A. Week 2: Mon=B, Wed=A, Fri=B. Go back to Week 1 and repeat. Do this for 3-4 MONTHS then maybe change up a few exercises. Then repeat for3-4 months. For best results, the only time you should change up your workout is when 1. You aren't seeing any results after 4-5 weeks (by results I mean strength increasing. You should see improvement each week or two in the weight being used or number of reps completed.) 2. You are injured or sick. Good luck.