Have the tool for over a year in occasional use. Mostly I use the small key and have been recorded neither wear nor I have ever had the feeling that threatens to cancel the Werzeug or bends. The keys are also completely clean and free of grease, therefore, and that is especially for "finer" work, as in my case, for example. with guitars, not insignificant.
I would like to highlight the clever clip to remove the key. Many other manufacturers have to remove a key first the neighbors are turned to the side, before you can pull out the candidate straight up. In this clip of election is simply tilted forward and can thus be easily removed and put back.