Yep. 30% upfront. But actually, once you show the customer what's involved, and give them a realistic estimate, it might reduce the chances of cancellation.

Yep. 30% upfront. But actually, once you show the customer what's involved, and give them a realistic estimate, it might reduce the chances of cancellation. The discussion might be steered towards what they really want, or prioritization of deliverables. A mockup (and multiple iterations thereof) might be necessary as well.