Time to make it pretty, but not before it's ugly.
Getting the blueprint and structure down for how a user might interact with the product. Laying out the architecture keeps the project focused by preventing scope-creeps, maintaining alignment, and laying the foundation for a design system. Depending on the aspect of the project being worked on at the time, the architectural level being laid out might be more or less detailed. Furthermore, the amount of documentation is best defined by the strategic approach to the design.
There are varying levels of fidelity, each of which may best suit a particular project depending on the priorities at the time. Low fidelity prototypes I’ve created have been as simple as sketches. While high fidelity may be fully interactive and include motion design. I ask myself "what we are trying to accomplish" to best define the appropriate level of effort at any particular stage.
TEst, Measure, & Iterate
Testing is the best way to validate key elements of a design before and after a product is fully developed. KPI’s that were established can be used when thinking about architecture to create a platform where we can easily measure user interactions. Insights gathered are leveraged for a continual process of iteration over a product's lifecycle.