We ship the order and PDF an itemized receipt with tracking number and the whole nine yards. He knows us and how we do business. He cuts the check instantly, and we recieve it about the same day as he receives the order.
I do realise that's a goods invoice; but that's just how I wish things would work in the web industry. As for delaying payment until you are sure things look as you want them; so far as I'm concerned, the moment the written specifications of the project are met the payment is collectable, whether the client loves or hates the results (quotation is based on specifications; same should hold for payment).
will the web industry become that way, especially if we let it?
In my experience, the web industry is already that way, especially when it comes to dealing with larger companies and government. The bigger question is how we reverse the damage!