During the initial requirements and design phase of your application, the best practice is to create user categorizations known as personas. Personas consider a user's typical skills, needs, and objectives. Using this information, you should also start to extrapolate their data requirements, such as the data they are responsible for creating (either directly or indirectly, by running processes), and what data they need to consume (reporting). Once you have done this, try to provide an estimate of the number of records that they will create and/or consume per month.

For example, in our FormulaForce application, it is likely that managers will create and consume data, whereas race strategists will mostly consume a lot of data. Administrators will also want to manage your application's configuration data. Finally, there will likely be a background process in the application, generating a lot of data, such as the process that records race data from the cars and drivers during the qualification stages and the race itself, such as sector (a designated portion of the track) times.

You may want to capture your conclusions regarding personas and data requirements in a spreadsheet along with some formulas that help predict data storage requirements (which will be discussed later in this chapter). This will help in the future as you discuss your application with Salesforce during the AppExchange listing process, and will be a useful tool during the sales cycle as prospective customers wish to know how to budget their storage costs with your application installed.