I'm not sure if I've just been unlucky but after Googling (I know, confirmation bias) I can easily find a lot of people with the same problem. The last two mice I've had have been Logitech, and both have failed in the same way, where left click stops working properly. Sometimes it interprets a single click as a double, and it often drops when dragging which can be aided by applying a *lot* of force, like a kg or something, to the button.
I'm just starting to question the general quality of Logitech mice and I'm not sure if I should try another or just go with another brand. The first was an MX620 which to be fair did last years before developing this problem so I could almost ignore it, but the M705 I'm currently using hasn't even gone through one set of batteries and has already become near-unusable! A quick look through Amazon reviews, without searching, reveals complaints of the same issue.
Now, the problem I have is I really like Logitech's scroll wheel - both the freewheeling and rocking. I could probably get used to doing without though.
So, what's your experience, and what would you recommend? I've been looking at the G402/G502.