It is an estimate; the same way that the appraiser arrives at stating in the sales grid that the condition of a comp is "Average".This has been discussed many times but the one question that always remains unanswered is "How did you arrive at the effective age for the comparbles"?
You can extract the effective age from the market, but of course, most appraisers don't believe in the cost approach nor do they think that land is appraised as if vacant and available for its highest and best use...thus haven't figured out how to estimate the contribution of the building, therefore they cannot figure the residual left in the improvements and thus cannot invert the annual change into a total life estimate...its impossible.:new_argue:"How did you arrive at the effective age for the comparbles"?
Then someone has been a naughty boy or girl and taught you the classic ways of long and short term depreciation. So see above. As we all know we cannot have any of that cost approach crap...:new_microwave:have been told that the age adjustment is for depreciation based upon age. A condition adjustment would be made if there is an unusual item like the need for a new roof or some other short lived item.