So, I do consider this question a bit different than most. I have an imac that I've had for 4.5 years. It's a great computer and it is still my primary machine. The last couple weeks, I've been reviewing craigslist and realized I can probably sell it for $700-800 (24" core2duo). So, this begs the question, if I plan on upgrading at some point, should I wait for a new model and take a risk that my current machine might have a failure? Or should I sell now before something breaks and put the money into a new machine? I have no signs that my current machine will die any time soon. I am just getting paranoid since it is getting older. As a follow up, is there an optimal time frame to sell in which minimizes the amount of $ per year for owning an iMac? Does anyone have a buy/sell approach that they don't mind talking about?