been using Logitech mouse for over a decade, been through many of their ranges and it is only 1 thing that fail every single time, the left click.
It is an infamous issue that Logitech never want to resolve, probably to sustain their sales, because they know consumer still goes back to them.

Tried replacing myself, most of the time with success, but the recent mouse M720 Trialthon is so difficult to remove the soldering, I fail to replace it completely. Now the mouse condemned and cannot be used anymore. But I still bought the same model as the price and function suits my needs.