When I was primarily living in China or Taiwan, I did change my laptop every two years. I didn't want to go through the pain of laptop repair in a country where I couldn't speak the language properly. Plus I was totally dependant on my laptop working. It was kept on 24 hours a day, 7 days a week. It got pretty cooked by the time a couple of years were up. I had the fans cleaned out every 6 months but it's not meant to be left on all the time.

Now that I am living in Japan and go back to Canada more often, I don't worry about changing the laptop as often. When it dies, I am confident I have options to purchase another.