Quick Question on WS4SB

hey guys, perhaps i read too quickly, but i couldnt find the answer i was looking for. when picking the exercises to use, do you use the same ones throughout the time you do the program,

Other than the max effort ones as he says to avoid burning out, or switch them up everytime? and how long do a lot of you guys do this program? thanks!

every 2-3 weeks you should choose other exersises on max effort upper and lower body to keep you from reaching a plateau. not sure if you change up upper body repetition.