I don't remember if you where involved, but this argument has been had before.
Some people believe that you always upgrade as quickly as possible to take advantage of new hardware and software. Other people avoid upgrading until the hardware physically fails.
I fall someplace inbetween, with a leaning towards the second. I don't think you should upgrade unless you have a reason. But I also think that at some point hardware and software becomes so outdated that it becomes hard to update, and you should move ahead enough to stay ahead of that problem.
Jay