A:Answer To be honest, it is too early to tell.
I've gone through 5 generations of the prior model (M570), and all of them started to have the "double click" malfunction within the 2 year warranty period. The cause was a very cheap, easy to replace - IF you have the equipment - microswitch. Instructions are well documented on the internet. But for those who didn't want to invest in the soldering iron and solder, and solder "sucker", Logitech was very good about honoring their warranty,
The new M575 hasn't been on the market long enough to see if it has the same weakness. Logitech claims they have learned their lesson and now use more robust microswitches. But by the same token, the warranty period on these newest trackballs is only 1 year. So it is still an open question which version of the lesson they learned.
