One of the sins of my old age?? Ok, many sins - but one I enjoy is putting on headphones connected to my iPhone and I play a piece that I'm working on with an artist I admire. For example, I learned the first contrapunctus from Bach's Art of Fugue - and played it with Glenn Gould and Charles Rosen. With the music in front of me, and listening/seeing what they're doing as I'm playing the keys, I find interpretive ideas that I missed when just listening to the music - or even things that are on the page that I may have missed or in some cases, the artist himself ignores - to a very positive result. Another piece I play - the Brahms Op 117 #2 was recorded by Brahms's favorite student - Carl Friedberg. Playing the piece with him - is playing it probably as close to what Brahms intended as is feasible - very helpful.
I didn't do this when I was studying with a teacher - but recordings did inform my playing. I remember working on Scarlatti sonata. As I played one of the ornaments a certain way, my teacher asked me why I did it that way. He said he had Juilliard student also playing the same work and she did the inverse of what I was playing. He noted that she'd researched performance practices at the library and found this to be the preferred way. I said, " I listened to Kenneth Gilbert's performance - as he had edited all of the Scarlatti sonatas - as well to Gustav Leonhardt and Vladamir Horowitz who all played it this way..." He smiled and said - "good enough for me."

