As a best management practice, it is always a good idea to conduct a requirements and benefits analysis prior to data collection. There are many studies on this topic. Below are a few studies produced by members of the Interagency Working Group on Ocean and Coastal Mapping:
The 3D Nation Elevation Requirements and Benefits Study is a partnership between NOAA and USGS. The 3D Nation Study documents topographic, coastal, & bathymetric 3D elevation data requirements and benefits from the tops of the mountains, to the depths of the seas, to include our inland rivers and lakes. This study will gather information to improve the availability and consistency of 3D elevation data (topographic or bathymetric data) for the United States and its territories. The effort will help develop and refine future program recommendations that would provide enhanced 3D elevation data to meet many federal, state, and other national needs.