[gnaffle]

Actually the opposite is true, apparently Mac users keep their computers for much longer than Windows users. A key reason is probably the price of a new Mac, another that time and OS upgrades generally don't make a Mac much slower (the exception being Lion). Many Windows PCs are simply thrown away because it's cheaper for a non-techie to buy a new one than to reinstall the OS an all their apps.

[pyre]

In the early 2000's, I knew a number of people that would upgrade every cycle or so by reselling their old Mac and buying the shiny new one.