We call these files “Cumulative Data”. Typically, they will be in a set of folders that just grow randomly over time. Often, they will be associated with projects or ongoing business processes.
If files are never accessed, it is possible you may want to move them into cool storage. Generally, it is most likely you would only move older versions of files.
Your Configuration file for Cool-It would need a Last Accessed Date that will be applied to the origin folders. You can make sure specific folders, specific files or specific file types are never moved if you know they should always be available online.