My experience was the same as @boneh3ad, I almost never used a calculator in grad school, and when I did, it was a TI-30Xa. The only class where I really had to use it, IIRC, was a course on numerical methods, which involved setting up an algorithm correctly, then doing a few iterations by hand (ie, by calculator) with numbers. Many of my professors didn’t allow calculators at all, during exams.
However, in this day and age, I’m not sure why you’d even want to use a calculator on an assignment to do things like integrals or linear algebra when you can so much more easily type it into Wolfram Alpha, which will solve and/or plot any symbolic problem/equation, or when you can compute/solve/plot it in Matlab or Python or something. I don’t think I’ve touched my TI-89 since freshman year of undergrad.