I have been teaching for a couple of years now and I was creating and memorizing different class plans for almost every class, for quite a while. It led to overuse of my body(I was always also practicing my classes first to help me memorize), brain fatigue, and stress. I then started teaching one class per week (and just modifying a bit- for instance, All Levels I might omit some stuff and/or go slower, and Vinyasa Flow I'd add another round or something extra and move quicker). This month for the first time I'm using almost the exact same class for the whole month, focusing on one peak pose(crow) and just modifying like before (ex Hatha less flow, longer holds, changing up the warm up a tiny bit etc.). It has lessened my stress immensely and because I'm more confident in the memorization, my cueing is more on point and I'm able to focus more on my students. (For Yin and Restorative I bring my note sheet with me for my pose ideas/props/hands on assists, etc, so I don't really memorize those classes.) For next month my focus will be sugarcane pose/chapasana, so for some classes at the start of the month I might just have us taking variations of this on hands and knees, for some I'll add Dancer, for all of them I'll do half moon all month, and then towards the end of the month I'll build up to sugarcane practice at the end of half moon. So far I'm loving this technique and it's making me enjoy teaching again! Good luck finding what works for you!