We're just concluding another symphony season and school year...time to make sure your student's flutes are in good shape. Normal 'wear and tear' issues, such as torn pads should be addressed. Check the cork position and have a qualified repair technician replace the cork if it is worn or sealing improperly. Review good habits with your students: Two necessary things: 1. swabbing the flute after EVERY use (I abhor those swabs that stay inside the flute body, trapping all the moisture) and 2. wiping down the outside of the flute once a day to remove all the finger 'grime' (skin oils, etc). I try to look at every student's instrument quarterly so repair issues are not getting out of hand. Have a list of qualified repair shops in your area to give to parents: make it easy for them to follow thru on repairs. Flutes that work correctly sound better!