One of the essential skills for any musicians is the ability to sight sing. It is invaluable to have the ability to be able to look at a score and hear the music internally, or to be able to sing the music aloud. A quick poll of several of my music teaching colleagues showed that while every teacher agreed that sight singing was a valuable and necessary skill for instrumentalists, only one teacher of the 12 present actively taught this skill in their lessons.
I find that the easiest time to start teaching sight singing is when a student is an absolute beginner to an instrument. [···]