As an engineer, I used most of what I learned in school, except Calculus. OK, technically I used Calculus concepts with respect to PID control systems, but even then I never had to take a derivative or an integral or solve a differential equation - I just had to know that derivative means instantaneous slope and integral is a summation.
I tell my engineering students that algebra and trig only solve 99.99% of the problems; for the rest, you need Calculus.