The fine printed line

So a thought that I have been thinking a lot about recently is how much variance performers should take from the written page.

For instance, I was playing the Hindemith Sonata for Horn and Piano in my horn lesson this week. At one point in the end of the second movement, my teacher recommended that on these three quarter notes, I should make a huge ritard (slowing down) on each of them and then pick back up the pace after I play the high note that they lead to. None of what he said to do was printed on my music, so I asked him why and how he knew about doing that and he said that it was just "tradition."

So how much "artistic license" should I take as a performer with a piece? Which begs the question: how much "artistic license" would the composer want/allow me to take?

Just thoughts...