My two N800's have been going strong for a year now.

Something that I've noticed that might make a difference is if you play a lot of video games. People who use game consoles a lot develop extraordinary strength in their hands and pretty much "squash" delicate electronics without realizing it.

My mother (who doesn't play video games, but does a lot of knitting and crocheting) regular mashes the buttons on her TV remote control and her desktop computer mouse requiring me to replace both frequently.