Concept stage site assessments based on exploration 3D seismic data and other existing information are critical elements in the deepwater field development sequence. Such assessments help create value by defining site conditions and geohazards that may eventually constrain development, which in turn allows risks to be properly evaluated before significant development decisions are made. Several decades of deepwater development consulting experience, however, have shown that-despite their great value-concept stage site assessments are often not undertaken because 1) decision makers do not know that the assessments should or could be performed, or 2) there is a misconception that money can be saved by skipping steps or executing steps out of sequence in order to fast-track a development. As shown by way of two examples, decisions not to perform concept stage site assessments-even in cases where the necessary data are already available and free of additional cost-can be expensive mistakes that result in project delays if surveys have to be repeated or field layouts changed. In other words, human decision makers become significant and-unlike those associated with geohazards-largely indefinable elements of risk if short-term savings accrued by doing it wrong the first time are prioritized while the potentially more significant costs of having to do it right the second time are marginalized.