I agree if you mean cost doesn't always equal value. (which I'm sure you mean) But for those lurking that might not understand, I'll add this to that. Your cost can't be lower than value...no one in their right mind would pay more for an existing garage when they can build a shinny new, completely to their design liking...for less. That would not fit the definition of market value where you have a buyer acting prudently, knowledgeably and assuming the price is not affected by undue stimulus...whereby: (1) buyer and seller are typically motivated; (2) both parties are well informed or well advised, and each acting in what he considers his own best interest.