When we need to do the art for a customer, there is usually a discussion of some length, to be sure we don't head down any dead ends. I'm sure most of us here have been there, done that. If we can't get something done in house, then I have no qualms in getting outside art. Of course, the customer pays for that, plus any additions we may have to do. But I do find that getting a good idea of what they want, even if I tell them to send me some kind of reference as to the style, goes a long way toward a happy customer, we involve them in the search.
Steve