“When will I use this?” is the common refrain. Whether it’s obscure knot-tying in Boy Scouts, SOH-CAH-TOA mastery in trigonometry, or the 18th Century voice leading that contemporary music majors are asked to learn.
I understand the question. We want to understand the applicability of the skill before we commit to spending time on it.
But that’s not how life works. I might discover a passion for knots that leads to a new hobby. My improving understanding of trigonometry is strengthening logical, analytical, and spacial parts of my brain, which will be useful in a large variety of other situations. The voice leading I learned in freshman theory has informed all of the music I’ve made since – most of it sounding nothing like Bach.
“When will I use this? isn’t the right question. The right question is, “Will learning this skill prepare me for what comes next?”