In order to achieve re-use of a TAS, where SHOULD the design for reuse occur?

The design for reuse of a Test Automation Solution (TAS) should primarily occur at the Test Automation Architecture (TAA) level. This is because the TAA defines the overall structure and design patterns that will be used throughout the TAS lifecycle. By focusing on reuse at the TAA level, it ensures that the test automation is designed with reuse in mind from the outset, which can increase the ability for reuse across different layers of the TAA.

References = The ISTQB® Test Automation Engineer (CT-TAE) certification materials emphasize the importance of designing for reuse at the TAA level. It is noted that while reuse aspects are already settled when the TAA is defined, the TAS can help increase the ability for reuse. This information is corroborated by discussions and consensus in the professional community, as seen in the resources provided by ISTQB and other educational platforms12.