My 11yo practices a rental bari sax at home. I'm not ready to purchase one yet because he likes variety. He did trombone in 4th grade, and I bought a used trombone for $150 -- that was fine. He played bassoon in 5th grade, with a rental. At the end of the year he felt satisfied and I returned the rental. It's too soon to know if he's going to want to keep going with bari after 6th grade. He plays the school instrument when he's at school. How do we check the rental instrument to see what maintenance is needed? The rental shop will do a better job with repairs if I give them specific suggestions about what is needed. I know something is needed because he says he gets better results on the school instrument. Thank you.