On this vertical mouse, which leads to a more gentle for tendons and joints hand position, I got used to very quickly. I do not want to miss. I had bought the mouse along with an ergonomic keyboard because I sit to work a lot on the computer. I had pain in the forearms, whether the many typing and / or mouse were serving fault, I can not say. The pain is in any case now almost entirely disappeared again and I really feel that my forearm remains relaxed when operating the mouse. The only thing still happens from time to me is that I overturn the mouse when I over to Kaffetasse long - it's just much higher than a normal mouse. That was at the beginning more often but also not a real problem. People with small hands it might be difficult for some, the mouse easy to lift when pulling in between, so it takes up less space. I've also done before and how many go with this mouse not good (although my hands are really not small). But you can use a mouse without lifting - I for example increases the speed of the pointer, and everything is fine.