How far back will/can a commercial appraiser go to find sales comps? How far out for geographic area?

For Commercial & Industrial Real Estate, banks typically frown on sales comparables older than 1.5 years (generally due to limited data, max of 3 years) and more than 5 miles (depends on natural boundaries, etc.).

Or whatever you can convince him to and justify.

Location (Land value), Property condition ( deferred maintenance ?) and Income generated. These are the main factors. Depending on the property for sale price, you can add some additional factors for in depth valuation.

As J. stated, there are several approaches to how an appraiser can valuate a property. If it is a comp-based appraisal, the appraiser has to use the resources available to them. In my opinion, that's why it is best ask for a recommendation for an appraiser that is local to the area and is familiar with the trends in the market. I recently had a deal fall through on a home because the appraisal was "low." In my experience with that particular market, (an area flooded by Hurricane Katrina that has been very slow to recover), the appraisal was dead on the money. But, due to the age and differences in the available comps, the listing agent convinced the owner to reject the requested reduction. That's the nature of the business but those are the pitfalls of appraisals. I hope this helps. Good luck!

In my experience most lenders only allow comps six months back. Geographic area is much more flexible if there are few close alternatives.

That is a good question and unique for each situation. I'm a private lender/ hard money lender and we do all our evaluation in house. I have used older comparables when they are justified, but there has to be a compelling reason to use the older comparables. I typically look at comps within an 18 month period in a very tight radius of the subject property (depending on location if the property is in a metro area there is typically not a need to go beyond one mile, in a rural area it might be 3-5 miles). In all honesty, if I have to go beyond the 3-5 miles radius and can only use older sales (assuming there are not newer sales in the area) we would likely pass on the transaction. Hope this helps.