The mouse was too smooth for the first week, constantly slipping out of my hands. It was impossible to lift with one hand. But then polished and the grip became confident. For 3 years, I changed the batteries only 1 time, an excellent result, given that I use the computer often and for a long time. On the wheel - after 2 years of use, a phantom click appeared. If you press on the wheel - the press worked, and if you click - it could work 2, 3, 4 and even 5 presses at the same time. A simple example: I click on the link with a scroll - 3 identical tabs open at once. If you press down the wheel not until it clicks, new tabs will fly without stopping. Because of this, I became nervous, even at work, on a different mouse, I click on the link and immediately check how many tabs have opened. If the mouse were cheaper, it would not be so insulting that you have to change it after 2-3 years. The mouse still works, but we are no longer talking about any comfort of use. Up: disassembled the mouse. There were no particular problems. Standard buttons - OMRON D2FC-F-7N - basic, Panasonic EVQP0E07K scroll button. In principle, you can fix it yourself, the buttons are separate, not without difficulty, but they are ordered. The textolite, however, is thin, Rosa needs solder. But I think that the malfunction of my mouse is not the fault of Logitech, the buttons are universal and are installed in mice from many manufacturers. The mouse itself, in general, I was very pleased, so I raise the rating from 3 to 5. It’s strange how the desire to save money makes you understand things that you didn’t even think about before.