I bought this on the 14th Aug 2011 now I've used this mouse practically every day since delivery for online gaming, CAD work (Maya & AutoCAD) and along side my Wacom tablet for photo editing (Photoshop, G.I.M.P.).
Well the list goes on, I write this review on 5th June 2014, it hasn't missed a click and nearly all the finish has worn off it. It's been great for my who has large meaty paws for hands to work with.
Thinking about it a lot of my stuff is Logitech and they're all still working and they are all slightly older to being way older than this mouse. Including my Logitech Z5500 I bought them in 2008(?) and they were second hand then!!