There are a couple of basic-compound-exercises that you cannot change. I keep those in my training year in, year out. Squat, deadlift, BOR, different kind of presses.
Instead of using the barbell every time, I regularly switch to dumbells. It's possible at our gym, they go to 200.
I switch the other exercises once every 6-8 weeks. You want to make some progress before you change. I don't think that's possible within those weeks.