When is the cost approach best used?
As you might guess, the cost approach is best used when the property in question is newer. That way, it's easier to find the figures for cost new and there's less to estimate where depreciation is concerned. Unfortunately, the more the property ages, the more guesswork is involved, and it becomes harder to find a valuation using this approach.
Notably, the cost approach is also well-suited for properties that are either underimproved or overimproved, as those types of properties will likely not be good candidates for the sales comparison approach and would need an appraiser to take a look at their unique features. Special use property, like churches and libraries, also falls into this category.