I've studied the large volumes of material on data warehouse ETL practices and have collected many useful thoughts along the way. When you combine that statistic with the palpable and sobering objective of a data warehouse as the “single version of trust,” good processes are essential. In the world of data warehousing, many industry journals report that Extract/Transform/Load (ETL) development activities account for a large majority (as much as 75%) of total data warehouse work. Those with experience will recommend these as practices, with the idea that following these practices leads to better, cleaner, and more productive outcomes. Nearly every professional endeavor contains processes and methods associated with carrying out tasks in that discipline.