
I was rummaging around this Christmas in a box of old university stuff I left in my parents' basement. I came across a Sharp scientific calculator that I probably acquired around that time - maybe 1990-91. It was so old, I'd forgotten I even had it. Looks brand new, and the battery is still good.
Meanwhile, I'm still using my TI calculator that I bought in 1985 to do my taxes...
I still have a TI 99 scientific calculator.