Do you feel that writers should provide a content piece for free for clients - based on the clients job request as part of the hiring process versus having them review your portfolio?

AFTER a client is qualified, certain acts of good will can serve as a valuable relationship deposit. A single piece of custom content may PROVE what a good portfolio promises. Entrepreneurs make investments. Some investments are financial. Others require your time. If you're currently in a position where the promise of this client relationship/retention is more valuable than your time, then you may consider what some industry professionals call "leading with a giving hand". Creating a custom piece of content may help your client mitigate risk and position you as the hero. :) Lastly, whatever you create as a custom sample of work is authored by you and remains your intellectual property unless otherwise assigned. If they value what you produce and want to make use of it, release usage rights in exchange for compensation. A true professional will do all possible to manage client expectations before, during and after the transaction. P.S. Have you heard about the Guardian creating a content marketing lab? http://www.seocial.ly/content-marketing-goes-mainstream/