When I did calculator in high school (2006 state champ, lol), standard was to have two calculators, one RPN and then the most powerful graphing calculator you knew how to use. At the time it was the hp33s and the TI-89. The RPN is so you can blaze through the number crunchers left to right and not have to mentally parse the order of operations first and for the word problems/geometry problems that you've mastered to the level you can work through them almost robotically, and then you call on the graphing calculator for anywhere you wind up setting up an integral or equation that is easier to let the graphing calculator solve numerically.
Looks like these days it's the HP35s for the RPN calculator and the TI nSpire for the graphing.