When I was studying piano at the academy, one thought kept returning as I played for my teacher: "Is this what he wanted?"
Whether I was doing the right thing depended on his judgement. I had delegated understanding to him.
If you do this, you are not engaging with the subject matter. Compare these two questions:
- Will my master like how I built that phrase?
- Was that phrase built the right way?
The first question piggybacks on the master's knowledge. He might have deep knowledge, but the only way to develop that yourself is by answering the second question.
How to shape a phrase can be a deep question. A good teacher can help you answer it. Sometimes the boundaries of a phrase are not obvious. Other times a phrase continues through moments of silence. A teacher can show you things you could not yet see on your own. Ultimately you have to rely on your own judgement though, even when it is wrong. Correcting your own faulty judgements is what learning is.
Otherwise you are just collecting facts about someone else's judgement.