Where do you get the license to interpret, say, Haydn?
Nowhere is it printed on the page that license is required , called for, or recommended. The need for it comes from the ear. That is why active, live listening matters so much. It is not the ear of repeated hearing that gives the permission--as in, so-and-so played it this way on the CD so that must be how it goes--but in, gee! that was really interesting!
When the mind starts to wander and the music to be repetitive it is the sign that the ear is not engaged.
Time to get a license!