The mere fact that any particular legacy code is still in use is a testament of its sustainability. Today we talk with Dr. Carola Lilienthal, the CEO of the Workplace Solutions and the author of Sustainable Software Architecture about the importance of a good structure for the durability of a software. Building upon her experience dissecting more than 300 software systems of various sizes, Carola shares with us her philosophy, methodology, tools and criteria for assessing the sustainability of a system and explains how to structure any software around its fundamental building blocks in order to achieve its durability.