Yes, in writing is the only way to make sure everyone is working from the same script.

I’ve not billed directly for phone time, but I do work that into the price. My contracts do include phone calls, but I limit them. I’ve been burned once or twice in the past by people who are addicted to the sound of their own voices, or those people who have to have a call to discuss the decision they intend to make if they ever stop having conference calls…

Billing for phone time helps here, especially because I send an email directly after the conversation, summarizing it, and stating if they came away with a different understanding, to say so within two business days.

If I’m not willing to do it, then I politely tell the client that this change does not work for me, and we should part ways. The client usually argues and tries to force me into what he/she wants. I re-iterate that we’re not a good match for the project and wish them well.