Have you ever did a job for a client, with full expectations being made upfront that once the job was over, payment would be made in full. Only to have that client come back to you asking, "Can you do just one-incy-winchy change for me?" - without being paid for that? For clients that you do not know, its pretty easy to say, "For a fee!", but what about if that client is a family member, or good friend? Do you do work "pro-bono"?