In Kelloo there are two ways to store custom data - tags and custom fields.
Tags can be used on projects, resources and work items. Custom fields can be used on projects and resources.
When to use tags vs custom fields?
While tags and custom fields can both be used to store custom data, they have different use cases.
Custom fields are better suited to storing data values that are specific to particular data record. Whereas tags are better suited to storing data values that could be used across data records.
Let us use an example to clarify how to use them. You could add a custom field to a resource called Employee ID. This is unique to that resource and would not be used on other resource records. So a custom field is ideal.
Lets say you want to record what skills resources have. These would be better stored using tags as the skills could potentially be applied to any of your resources.
Resource, project and work tags can also be used to filter the planner, whereas custom fields can't be used as filters.