If we are honest to ourselves, we realize that any precision device is prone to operational "hazards". In the case of valves that can be not brushing our teeth, not regularly cleaning the horn PROPERLY, not oiling the valves properly or often enough. Remember that foreign materials in the instrument wander over time and not brushing your teeth today can cause a hang next week. I have also often noticed that most trumpet players do NOT oil correctly. They just pull the valve out a bit and oil on top of the moisture and grunge. One really needs to wipe the valve AND casing everytime and then oil the CLEAN, DRY metal directly. Oil floats on moisture and that causes increased wear and worse performance. Comments like I "hate" border on ridiculous as they blame fine hardware for shortcomings on the side of the owner. The pros that I know using Yamaha instruments praise the valves - but then again, when you make money with the horn, you tend to avoid things that could change your reputation! Let's keep the thread serious instead of documenting our own laziness!