Single sourcing is a method for systematically re-using information. With this method, you develop modular content in one source document or database, then assemble the content into different document formats for different audiences and purposes.
Although its primary goal is to save time and money, single sourcing improves the quality of your documentation.
Reduce redundancy by having one source of truth for each information. This way the written information is more easily reusable in other documents and - which is even more important - it is referenceable. Single sourcing demands automation.