Back in 2017 when I joined the Pomelo team, the app's design was not fully documented. Most editable files were Illustrator files and a few pages were just directly built by Front End developers without design guidance.
As soon as my questions about CTAs usage got repetitive, I started a UI Inventory, along with the design of some screens and user journeys on Sketch. But soon I got immersed in daily business activities and I was only designing specific screens that were needed for a feature update. I couldn’t focus on the design structure definition anymore.
When a new designer joined the team, she started asking questions about design consistency. Even if it was exciting, I felt embarrassed about my answers the truth was we didn't have a library of visual components and patterns.
We also didn't have the experience defining guidelines of established software, but still, we had theoretical knowledge about Design Systems and we were aware of the fact that we were wasting time on repetitive UI tasks. With each upcoming project, using Sketch and Zeplin, we cleaned the screen's design by reducing visual patterns; we were working hard and soon the workflow became faster.