You can use Categories and Areas in any way that helps analyse your workload and make decisions about what to do next or where effort is needed.
Categories and Areas are edited in the same ways as Contexts and Owners:
Categories entered in the ResultsManager Edit dialogue are copied to the Categories field in MindManager's Task Info task pane, and can be re-edited from there or made available to other task management applications. Areas are not stored in a visible field, and are only accessible through the ResultsManager Edit dialogue. Both Categories and Areas have their own Master lists that you can keep up to date.
Categories and Areas can be used to collect together related items from separate projects when building dashboard maps. They may have some common attribute that helps you during your weekly review, without necessarily making them into a project on their own. For example, you may have lots of action items related to your business, organised into projects, but only some of them contribute directly to revenue generation. Instead of duplicating these actions in a project that is focused on driving revenue, you could create an Area called "Revenue" and assign certain tasks from other projects to it. Then in the weekly review you could get an overview of all the individual actions and sub-projects that are revenue-generating, collected together into one list.
Choosing which to use
Although Categories and Areas appear to be similar, there is a basic difference between them. ResultsManager treats them differently for the purposes of organising Activities in Dashboard maps. Area settings are inherited cumulatively within the map, whereas Categories replace inherited settings.
The Category or Categories assigned to an Activity will either be the Categories explicitly assigned to it in the Topic, or if none are defined, the Categories it has inherited from its parent topic will be used. If Categories are explicitly assigned to a Topic, then they will replace any that are inherited from its parent in the map.
For example, if an Activity has the category "Improvement", and a subtopic has the Category "Bug Fix" assigned to it, then the subtopic's own category will replace "Improvement" that was inherited from its parent.
Areas work slightly differently. The Area or Areas assigned to an Activity will be combined with those inherited from a parent. So the inherited settings are not lost, but are added to.
If an Activity has an Area of "Management Meetings", and has a subtopic with the Area "Weekly Meetings", then the subtopic's Areas will be regarded as "Management Meetings; Weekly Meetings". It will retain the Area inherited from its parent and add its own to the list. When it is displayed in a Dashboard that organises Activities by Area, it will be listed under "Management Meetings" and "Weekly Meetings", even though it only had the latter assigned to it explicitly.