I would like to share the experience of a group of technical writers who worked systematically on content modularization (topic-based writing / structured authoring).
The company's user manuals had a history of more than 20 years. The existing user information was in the old-fashioned book-writing style, redundant, and became more difficult and error-prone to maintain.
To solve the problems, more than 4000 pages of obsolete user information were consolidated, 100% re-organized, and re-written using the topic-based approach. The re-writing was done intermittently during the past 5 years.
Finally, ~2000 topics of the state-of-the art modular content were created, with high quality and the flexibility for the maximum reusability, for all the user information of the company's all products and for all projects.