You're correct that "utility"-type depreciation isn't that fast when it comes to the day-to-day, but "business profits" don't typically (ever?) take that into a

You're correct that "utility"-type depreciation isn't that fast when it comes to the day-to-day, but "business profits" don't typically (ever?) take that into account in the calculation. So it's really two different things. As an aside, here are the BEA's depreciation rates: http://www.bea.gov/scb/account_articles/national/wlth2594/tableC.htm http://www.bea.gov/scb/account_articles/national/wlth2594/ta... None of the above take into account the "utility goes to zero" fact for certain computer hardware: i.e., if a machine winds up too slow to run the latest software because of ever-increasing system requirements, the practical value of said hardware can go from "less than recently calculated resale value" to "possible resale value of raw parts" or even "zero."