Granularity - one file per topic

DITA topics should be saved as individual files, and the ditabase composite topic should be avoided.

Each DITA topic should be stored in its own file. Although the ditabase (or composite) topic type technically permits multiple topics to be nested in a single container topic file, this approach should be avoided. The smaller the topic unit, the greater the opportunity for re-use.

Although it is possible to use the chunk attribute to merge multiple DITA source topics into a single output topic when publishing to topic-based formats such as XHTML, the simplest approach is one source topic to one output topic.