I record myself most days when I practice the piano. I just use my phone, and even though I have been doing this for years I still often surprise myself. When we are playing the piano we are too busy to truly hear what we are doing, and the body movements that we are making can influence what we hear. The phone records what we are actually doing, and we can listen back at our leisure and hear exactly what we sound like.
One of my teachers once told me that one way to identify a great musician is that what they think they are doing when they play matches what they are actually doing. Surprisingly this is rarer that you might think. I’m sure you have played in piano lessons, and your teacher has asked you to get louder, and you think you did, but actually it was all in your head, and the music didn’t get louder. I see this happen every day when I teach.
This is why recording is so useful. It shows you what you really are playing, and not what you think you are playing. And this is so helpful because it lets us hear exactly what our audience hears.
As I said at the beginning I often surprise myself. I think I'm playing something perfectly, and when I listen to the recording I notice things that I don’t like. It is actually really satisfying, as you get to fix your music, and get it to sound exactly how you want it. It is rather like a chef tasting the food that they make to ensure everything is perfect.
I recommend that you record yourself often. Sometimes I record the whole piece and listen, and sometimes just a small section, but more often than not I find a way to improve my playing that I hadn’t noticed before I recorded myself.