I have a Razer Deathadder 1800DPI original edition and still use it to this day. I bought it in 2007 October. My brother also bought one and he used it for about 5 years when the left button started double clicking at times and wouldnt have a perceivable click.
Mice are basically like stationary, they are not supposed to last forever, but my deathadder lasted for almost 7 years now and still going strong. I recently bought a replacement Steelseries Sensei 11,400dpi mouse but sold it because I felt that my deathadder was superior and much more pleasant to hold and use.
I am planning to get a deathadder after this one dies, whether it will be 2013 or 2018 edition depends on how long this one still lasts. Best buy ever.