When I bought a new Boss TU12H tuner back in the mid 80's - it came with a frequency chart that provided the exact frequency for every note on a piano. I was living on the road at the time, so time was something I had plenty of... I will never regret taking the time to learn (and understand) that chart.
To this day I get stunned looks from sounds techs and monitor techs when I identify and name a frequency I want rolled back - or when a blast of feedback hits I promptly name the frequency to lower after matching the note on the guitar. I guess should add that I also had to learn to compensate this knowledge to apply to a 31 band graph.