How and why do you use your HP calc?

[HP67]

I bought an HP-67 in 1981 before going to college. I used it for a few decades. I remember aceing the Amateur Radio General and Advanced Class licenses in one sitting at Motorola with that calculator.

I bought a 12C on the way to buy a new car one day in the mid 1980s. I caught a problem with the financing and the calculator paid for itself about 30x. I still use the 12C for personal finance.

Much later I bought a bunch of other HPs. I use a 50g for programming astronomical algorithms and a 48G (haven't found a GX but would like to buy one in perfect condition) for desk use since it is much faster to use than the 50g.

I got a DM-16L recently and I use it very often at my job since I write and debug software written in assembler. I don't remember why but I bought the TI Programmer in the early 1980s and did not get the HP-16C. The TI was junk and fell apart after a few years of daily use but showed signs of sickness not long after the purchase. I have a friend who bought a 16C in the old days and still uses it. I hope my 16L will last.