How often do you upgrade your development PC? I upgrade mine every 3 years or so. I'm just curious. Do you upgrade when you find your computer slowing or for other reasons?
I tend to upgrade only when something goes horribly wrong or when I am limited from doing something. This is probably because I like to use a laptop for development purposes.
I still have a bunch of old kit hanging arouind though. My theory is that ideally my latest code will run acceptably on that old JVC mininote with 768MB RAM and 1 1GHz processor. If it runs well on that, it will almosts definitely be OK on my target systems.
When I'm bored with my current computer. Typically every 2 or 3 years.
When my wife allows...
I only upgrade when the components are spoilt. After weaning myself from computer games, I find not much need for upgrading hardware. But more ram is always welcomed.
About every two and a half years, although it can be a pain to reinstall everything and realize just how many tools you actually use. This last time was about speeding up by taking advantage of dual core, as well as getting a quieter environment. I reduced some of the reinstall by putting the old machine in the closet and using it as a standby/part-time database server, thus avoiding reinstalling/migrating the databases that I rarely use. Then I can flip it on when needed.
When the processor speed, memory, and hard-disk space of the new PC has doubled by comparison to my old PC, and the price has dropped by at least a quarter. Usually this comes out at about 2-3 years, but now the extra processor speed equates to more cores rather than more linear speed.
The other reason is where I need to do a major compiler / dev tools upgrade and the new version is liable to kill my existing development environment. In this case I get an extra PC. I really have to get my head around virtualisation one of these days.