I'd like to see graphic curves over time for the resale value ? say Gazelle ? of various Apple products over time. This goes to how long the products hold value, and how the initial steep drop levels off. This can affect buying cycles and help people decide how long in general to hold onto their devices. This can also take into consideration memory, drive, and processor upgrades. My suspicion is that for resale value you want to minimally upgrade your device, but for personal use in the meantime upgrades can be of great value.