It's important, I think, to understand portfolios in terms of what they are - a tool to get work. The type of portfolio, what goes in it, and what is okay to include (as well as in what form) all depends on the kind of work you're trying to get. I think as a rule of thumb, it's always important to show respect for the time of the person going through your portfolio. So, in that sense, WIPs could add clutter and become somewhat distracting, making it harder for that individual to gauge you at a glance. If we're talking about a digital portfolio - a website, a PDF, etc. - then there's always the opportunity to provide a deeper look at a given project, how it was iterated upon, etc. via a link that does not detract from or diminish the standalone portfolio itself. If that's the case, then I would still recommend making sure that your WIPs are not arbitrary. They should all serve a purpose, serve to communicate some aspect of how you solve problems, and how you thought through a given piece. If you did work for a client (for which you received permission to share), there *might* be some value, for some people, to see how you engaged with feedback, how you handled revisions, etc. But still, all of this is very much secondary to the main elements of the portfolio that a potential employer or client would want to be able to traverse as quickly and efficiently as possible.