Knowing When it’s time to switch up your routine: the first two questions I have to ask are 1-“are you still experiencing gains/progress.” 2-“are you experiencing pain that is possible from an overuse injury.” The answer to the second question could be changing exercises. Exercises from different angles can hit the same muscles. But I like to think of the joints and angles of pressure put on them being like a drip of water on a stone, if the pressure and strain on the joints and bones is always at the same angle you might be wearing down that same spot over and over.
To the first question, “are you still experiencing gains?” If the answer is NO, Don’t immediately look to the workout itself, first think about other factors. Your workouts do not happen in a vacuum. You have all types of stress, and most likely inconsistencies in your recovery. I swear I can have an identical diet and training protocol from one week to another and let’s say one week I get 6 hours of sleep and the next I’m getting 8, I see significant differences. This example is highly subjective but I swear I see cuts and muscles more filled out with everything else identical but I’m just sleeping more l. In fact science supports this theory as well. So, don’t always look to just the workout, look at your whole human biological experience.
It might be time to mix it up if you’re not having fun anymore! If you’re not going to be a powerlifter you don’t necessarily have to straight bar bench press. Switch it up, depth jump push ups, TRX push ups, dumbbell work, and even the Jacobs Ladder hits the chest. If you aren’t going to be a powerlifter you don’t necessarily have to barbell squat. Everyone needs to do some sort of squat but the variation can change. My recommendation for general fitness is to cycle a different squat every 4 weeks unless someone has a specific goal of adding weight to a specific style. Personally I start a clients squat journey by teaching the front squat first. Reason being I feel this is the most intrinsically less risky and practical. Less risky because if form seriously breaks down the weight simply falls. More practical because many of my clients lift something up in front of them (heavy hag, object, or child) but rarely do they ever throw something on their back and squat it.
So to sum things up, it’s time to change things up in my opinion if you’re: hurting, not making progress, or bored. Other than that keep getting after it!