Defining a "designated user community" for a data collection is essential to good scientific data stewardship. It enables data managers to determine what information is necessary to ensure the usability of the data now and into the future. It helps managers present and enable access to the data and may determine the format of the data. However, defining a community is difficult, and it is impossible to predict how the use of a data collection may change over time. This creates a series of data management problems for data stewards that may be mitigated by a set of best practices.