One of the world's foremost saxophonists and educators, George Garzone (USA) at The Music Place South Melbourne recently.
The most common cause of bent instruments is an incorrectly fitting case. Even without being dropped, a case that does not fit your instrument correctly can cause damage and bending to your treasured instrument.
A bad fitting case can either be too loose, which will allow your instrument to move around inside it, or too tight, which will apply undue pressure on the instrument in places that aren't good for it. There is a quick and easy way to tell if your case is too loose …. Close the case and gently (gently, gently) shake it. If you can hear or feel the instrument moving inside, the case isn't the right one. What will happen is that when you are carrying your instrument in this case, the contents will move, just as it did when you shook it, which can result in bent keys and posts (and even a mildly banana shaped body).
If the case doesn't rattle at all, you need to check where the instrument is resting inside the case and which parts of the instrument pressure is being applied to. As a general rule, if the instrument is resting on any of the “sticking out” keys (eg. Low Bb/C#/B/G#, palm keys on a sax) it is an incorrect fit. Also if there is excess pressure on the top half of the body, pushing it sideways this is incorrect. Even the original manufacturer’s case may not be the best or most suited case for your instrument. Cases can also wear, mouldings compress or become damaged over time thus reducing their effectiveness. If you are even the slightest bit unsure it is best to ask a technician to have a quick look for you. If you are travelling long distances, or on a plane or bus, it is advisable to see or speak with your technician to discuss the best way to pack your instrument.
Remember, when buying a new case, take your horn along and check!