How and why do you use your HP calc?

[Dave Britten]

I generally like them because they allow a great deal of customization for your workflow. For example, on a 17BII, 27S, 19BII, etc. the solver lets you add functionality that closely mimics the built in tools. Need to be able to do computations for an annuity with an interest rate that changes after a set number of periods? Just type in the equation.

It's similar for the scientific models too (excepting the Prime, of course). Programs that can manipulate the stack and system state, custom menus, user key bindings, etc. You can get your work done with a minimum of keystrokes and memorization of manual routines. My one lament is that HP has never included very many statistical regression models. They could at least add polynomial, sinusoidal, and logistic (I think I noticed the Prime finally has a lot more, fortunately). I also wish the RPL models had better support for interactive, "terminal I/O" kinds of programs, like one might do on a TI with Disp, Input, and Output.