Overview
The case is the basic unit in FogBugz. When creating a case it has to be assigned to a Project, an Area, a Milestone, and a Category.
Sometimes it is confusing what is the best approach to organize our cases around these case properties.
Information
Project and Areas provide categorization on the axis of function/feature group/modules. Eg: to which product or feature set does the case pertain.
Projects can be organized into Project Groups providing an additional level of organization.
Milestones provide categorization on the time axis. Eg: when a given case is planned to be delivered, in which Release, or which Sprint.
In the article Projects, Areas, Milestone you can read more about projects, areas, milestones, how they relate to each other, and what best practices we recommend when using them.
The case Category provides a categorization at the work unit level. Eg: is it a bug, feature, enhancement request, etc.
Cases can be organized in parent-level structure using sub-cases.
Cases can be tagged, providing an additional flagging type of flat level of categorization/filtering. It doesn't matter in which project, area, milestone, or category is the case, when filtered on a given tag, it will be shown in the search result set.