I have several slide rules. I use them all the time, even now I'm working one with each foot while I type this. As for accuracy, well, they were good enough to build the Empire State Building, to fight WW1 and the Hun Hordes, build the Atom Bomb and the first Atomic Pile, to construct Boulder Dam, to figure out all those books of logrhythmic tables. BY GOD! If it was good enough for Isaac Newton, Michael Faraday, Madame Curie, Louis Pasteur, Enrico Fermi, Lis Metner, and Werner Von Braun it's good enough for me!

Now, addition and subtraction are, well, problematic....