My university students are sometimes unconvinced of the value of their core music curriculum. Like most music programs, the core at my school includes music theory, applied theory (aural skills like sight-singing and dictation, and piano/keyboard skills), and music history. Most of my students will be educators, like I am (most of them will teach music at a middle or high school level). Here is just a small handful of the ways that, as a teacher, I use my undergraduate music skills on a daily basis.

• Evaluating student performances (aural skills, theory, history). Sometimes when I pick out a wrong note in a student’s performance, they express amazement that I have so much music “memorized.” I don’t. But I can follow the score and tell when what I’m hearing doesn’t match.
• Preparing lectures, presentations, program notes, and so forth (theory, history). What makes this repertoire piece, this composer, this technique, this performance practice important? Context is crucial.
• Selecting appropriate repertoire (history, theory). A good student recital or ensemble concert needs to balance the students’ educational needs and the audience’s attention span. And even once the repertoire is chosen, a broad-based musical education is key to differentiating between published editions.
• Arranging, adapting, transposing, and transcribing music for soloists or ensembles (theory, aural skills, keyboard skills). This can be elaborately creative or simply functional. But every working musician and music educator at least needs to be able to take a given piece of music and make it work for a different instrumentation, taking into account instrument ranges, chord voicing, and balance.
• Making and communicating interpretive decisions (theory, history). Good interpretive decision-making can mean following the “rules” with strictness, or making informed decision to bend or break those rules. Understanding the canon—insofar as one exists—of performance practices, and having the vocabulary to discuss them with precision, helps tremendously in either case.
• Demonstrating musical effects for students/ensembles (theory, aural skills, keyboard skills). Good music teachers don’t let the instrument(s) collect dust, even if their primary outlet is as a conductor. Music is an aural tradition, and a “picture” is worth a thousand words. (“Instruments” in this situation includes the voice, for singers and non-singers alike.)

That list is teaching-focused; as a performer I use all of those skills just as much, if not more. Study hard!