All musicians practice ear training constantly, whether or not they are cognizant of it. If, when listening to a piece of music, a musician is envisioning how to play it or is trying to play along, that musician is using his or her 'ear' - the understanding and recognition of musical elements - for guidance.
Steve VaiI loved the guitar, and I had all of this music in my head. My passion for the guitar and the ideas for what I could create musically were equal. So that's where I was.
Steve Vai