Sometimes I find my calculator does not calculate correcly, which is annoying!
I’ll bring 2. One I have been using for 2 years and a brand new one.
Paranoid people do. The chances of your calculator dying on the exact same day as your exam is as close to zero as possible.
I’ll probably just change the batteries ahead of the exam. Last year there were a few extra calculators in the exam room, but I would guess you should not count on that being the case for all exam rooms.
Better safe than sorry.