Will a TI-84 or similar graphing calculator ever come in handy in software development, or will I only ever need it for school?

I never used a graphic calculator again after school... but I used a lot regular calculators - just because they are not on the screen that I need to display other documents.

I'm much the same as Kathy. I haven't used mine for anything work-related. The experience did lead me to look for good software to perform similar functions, and it took a while to find good ways to make graphs and find intersections and so on, but a computer is usually superior.

I have yet to find a reason to use it. Chances are you will do basic calculations and nothing that requires a sophisticated calculator. More so, built in macOS app Grapher and the variety of different calculator apps should do the job if you find yourself in need of a calculator of that caliber!

Agree with all the comments above. One thing that may be helpful in your future is to make sure you know how to do everything you do on the calculator in MS Excel... That may prove very useful in the future.