Expectations have to be clear on both sides, and for that you must have a specific scope of work and a creative brief that have both been approved by the client. These will be your best tools for avoiding the dilemma of open-ended change orders. The purpose of these clarifications is so that you can control the process. It is true that you are working for the client, but once hired and with the above documents in hand, it is your job as a professional to make sure the project proceeds properly. Clients (generally) aren’t equipped to do this – that’s part of what they hire us to do.
A defined scope of work (including a specified number of approval rounds) will allow you to say, “I would be happy to make these changes. However, they will constitute a scope change. Would you like me to give you a quote for the extra work?” Clients often assume that looking at drafts is like buying shoes: they get to try new ones on ad infinitum until “they are happy.” You have to be clear about the difference – part of our job is to avoid wasting time by trying ideas that we know are not going to work, without alienating clients.
A signed-off creative brief will allow you to say, “I understand that the idea of adding a fuzzy kitty to the home page seems appealing. However, according to the goals you approved in the creative brief, this addition would destroy your credibility with your target audience.” That makes them aware that they will be solely responsible for the results of their own bad ideas. When you bring these issues out in the open in a professional way, you will be better able to guide your client to productive decisions.
As to showing drafts: I NEVER EVER send drafts to clients for them to look at on their own. This is a sure road to disaster. It is absolutely imperative that you walk them through the work, whether in person or on the phone. You must be on hand to explain your thinking and head off any fuzzy-kitty ideas. If I can’t meet in person, I let clients know their draft is ready and set up a phone meeting. I email the pdf 5 minutes before our meeting time. I can then explain why I did what I did in a way that discourages tangents (“What about horses? I want to see a horse!”), and show how it supports the goals in the creative brief. We are both able to ask questions, make suggestions and get/give feedback in real time.
The main cause of wrong turns and misunderstandings in a design process are the assumptions that fill the void created by a lack of clarity. For designers, that is job one and it begins at home. Nature abhors a vacuum and never more so than when it is caused by poor communication.