<p>Late design changes cause rework when the people building do not learn about them until they hit the change on site. Comparing revisions moves that discovery to the model.</p> <p>Every export in BidLight is a versioned snapshot. When a change lands, you compare it to the previous revision and see what moved, element by element, grouped by category.</p> <ul><li>Publish after the change instead of overwriting the last file.</li><li>Compare it to the revision the field is working from.</li><li>Pin an issue to each changed element that affects work in progress, and tag the person who acts on it.</li><li>Let the 6am digest carry the issue to its owner.</li></ul> <p>Rework you prevent is cost you never see. A clash caught in the model costs about $50. In the field it costs $5,000 to $50,000.</p> <p>You also stop the version confusion that eats about 11 hours a week on many teams.</p>