This is why I had 3 calculators in highschool:
TI 83
HP 11C
Omron 12SR
I did nearly everything on the Omron (provided I was sitting near an electrical outlet so I could plug it into the wall). The thing was so slow that it meant I had to do the actual math myself and then check it with the calculator. I ended up being one of the fastest people in my calculus class, because I never bothered to learn how to make the TI-83 integrate for me.
It has paid off well.
PS: Yes, the calculator really was 8 years older than me.