Right now I have a 12" Powerbook Rev. A running 10.4.8. I don't see myself upgrading anytime soon as this system does everything I need it to. I tend to be rather slow in upgrading software, often skipping several versions so I can usually get along with older hardware. In fact, I don't see a good reason to buy 10.5 when it comes out. My question to you folks is this: What criteria do you use to decide to get a new computer? Do you need the latest hardware? Run it till it dies? Replace every two years? What is your philosophy?