But the other thing about the TI-8x line is if you take a short amount of time you realize you can program the hell out of it. So if for example you're required to memorize formulas, just program them in.
This is exactly what I used to do with my TI81(?) back in 1993 when I was a senior in HS. I was one of the few kids in my class to realize that you could actually program your calculator. When it came time to learn a formula, I would write a program using that formula. Two birds killed with one stone: I had to understand the formula to write a program for it and simple math errors were largely avoided because I was just plugging in numbers and letting the program do the operations. I would do this for chemistry, physics and economics.
After some time, the teachers became aware that some students were just storing equations (not programs) in their calculators and would walk around to make sure that everyone cleared their calculator's memory prior to a test. The solution? You could make images and store them so I wrote a program that made it look like I had cleared my memory.