I don't quite look at it that way... I think we sell our expertise in utilizing the local land records and our knowledge of real estate law to know which records are important enough to include in our search results.  To some extent, it could be boiled down to the time it take to do that, but I think that is selling us short - we are more than just time.

In addition to expertise and knowledge, I think we should also be charging for the liability we incur.  We pay a lot of money each year for E&O insurance and we should be compensated for that as well. 

Given my theory on what we charge for - expertise, knowledge, and potential liability - I don't charge clients for "no-finds" or "returning documents."  Neither requires any special expertise or knowledge and we don't incur any liability.  And, as I previously mentioned - nobody is going to make any money on those things.  I'd rather bill my clients for services that we can both profit from.

That being said, I could understand charging a fee if these things happen often with the same client.  Sometimes, an extra fee is the only way to get a client to change the way they do things.  But, for us, it just hasn't been a problem.... once in a while we have a "no-find" or have to return a package because we couldn't record it... in those cases, we just consider it a courtesy and do not bill the client.