&gt;Building construction is also fraught with unexpected events and project management issues etc., but I&#x27;d laugh any building who would propose that I just keep paying them until it&#x27;s done,<p>In practice, though, this is <i>exactly</i> how building construction and civil engineering works. After all, if the bridge is half-built, what&#x27;s the customer going to do? Walk away? When was the last time you heard about any large civil engineering project coming in on time or on budget? It&#x27;s to the point where we&#x27;re relieved when the project ends up within an order of magnitude of its projected cost.