I don't really know what conclusions to draw from this table; I do see that after I started buying new laptops I retained them much longer than my used and refurbished laptops. On the other hand, I probably spent 4x as much on my previous laptop than on the used Dell and I've used it about 4x as long.

From the records of my last few purchases, $700 appears to be what I'm willing to spend on a desktop machine, and $1200 is what I'll spend on a laptop. In the latter case, what I require is a very high resolution screen, so it's a tragedy that the 1920x1200 15" screen is no longer available on any new laptops.

I haven't used a "desktop" machine as a desktop at home for years; rather, every system since the Sempron 64 was a "server" machine that just happens to have X installed on it for the few occasions that I sit down at the console. While I sometimes spend time pricing systems with newer CPUs, I really don't need more power on my server—The CPU's been approximately 93% idled over the last 45 days and the disk has been 97% idle (atop 'activity since boot' numbers).

I guess the moral is that I should learn to stop looking at new hardware; it only risks that I'll buy it without needing it. Only in a minority of cases did I buy new hardware because the old hardware had failed. In many cases, my justification more a new technology (64-bits, multi-core, etc) than a specific need.