With the release of the new iBooks today, I started thinking about computer buying cycles. Common wisdom seems to be that a computer should last 2 to 3 years, but Im wondering what cycle is the most cost effective when buying a new computer. Im thinking there are three basic options: Option 1: Buy a new computer every three years. Try to sell 3 year old computer for fair market value, probably a couple of hundred dollars. Option 2: Buy a new computer every three years but upgrade mid cycle (ie. upgrade Panther to Tiger and add more RAM). Try to sell upgraded 3 year old computer for fair market value, probably only slightly more than in Option 1. Option 3: Buy a new computer every year. Assume upgrades will come standard on new computer (ie. Tiger and more RAM). Sell 1 year old computer at fair market value, probably more than Option 1 & 2. I doubt there is a firm answer here, but what has been everyones experience?