You should never be content in your training. I am always looking at what other bodybuilders are doing, always trying to learn more about what workouts are more effective, or which ones target muscles better. You can ask my wife, I’m always changing things in my diet, adding or removing calories etc. And you should be too.
If you are new to working out, then yes stick with one thing until you get into a routine. But once you have the routine down start changing things up. Do drop sets one week (Do as many reps as you can at a max weight, then drop the weight down and do as many reps as you can, repeat this till you are at the lowest weight).
If you always run inside, try running outside on a trail or a track. If you always bike, try getting on the elliptical. Increase your reps one week, and your max weight the next.
I’ve been lifting for years, and I still am not where I want to be, because just as my body evolves, so does what I want to attain. Change is good. Keep your body guessing, keep your muscles questioning what you are doing. And never quit learning.