When starting out I would turn down work or pass to other creative professionals. Over the years I learned never to turn down a lead (unless its not a fit) and to facilitate the relationship with the other creative professional. This allows you to stay in control of the project/relationship, solves the problem for the customer and builds a great rapport with both parties. This isn't recommended if you cannot trust your network of creative professionals (regardless of the industry) as their efforts reflect on you.