From a book on running but also applies to playing guitar.

“How slow is slow enough? This question can be answered by another question: how slow do you need to go in order to discover something new? Consider that slowing down is simply a tool by which you can become aware of things that you were not previously aware of.”

— Slowing Down to Run Faster: A Sense-able Approach to Movement by Edward Yu a.co/iRsrBKg