bought the mouse 2012, and used intensively for 3 years. Must that I was blinded by the design say. Because slowly but surely occur more and more mistakes. Recently, the thumb buttons are me draufgegangen. They have been around for years, no more clicking sound. Does not bother me wieter, but now they are beginning to appear to stop responding. that's a problem. The mouse I could never adjust to the length of - was broken from the start.