At which point HW has devalued itself only by 20-25% worth.
Not very long.
I have been thinking that it's fair to consider a 40-50% resale value on all mining hardware purchased, more in cases of super high end things like 6990s.
Some pool-mates and I were talking today about the idea of colocating mining equipment. Considering things like electricity and cooling, it's a great idea.