Somewhat related, a few weeks ago I managed to fix a Microsoft Sculpt Ergonomic mouse which I've been using for about 3 years. I would have to click a few time

Somewhat related, a few weeks ago I managed to fix a Microsoft Sculpt Ergonomic mouse which I've been using for about 3 years. I would have to click a few times before it would register one click. Very annoying. Just like in this post, the problem was the switches. But in my case, the switches were micro switches. Not knowing where to order the correct parts and having no soldering skills, I decided to pry open the micro switch. Luckily it was possible. Taking the metal cap off, inside the switch there was a rubber membrane and a flexible metal disk. The disk was similar to a jar lid. The edges would touch the circuit board, and pushing the center of the metal disk, it would make it touch some conductive part of the board and it would "close the circuit". The problem was that the flexible metal disk inside the micro switch was dirty. Oxidized, probably. I cleaned it, put the switch back together and the mouse works perfectly.