Advance payment, nothing else can be better for a first time.
For every time.
Fixed it for you :- ) Advance deposits simply need to become standard in this industry. In 4 years I've never been refused a single time, but the more this will become universally accepted practice, the better.
Yup. You are totally right :) I actually do this with every new client, every time. But feel quite uncomfortable with long-term partners, since they've never missed payments. On the other hand, there is always "a first time" which might be very paintful :)
I actually see archviz no difference from any other product/service branch, so we should practise it easily :)