Faced with the question of "Should I go with a brownfield approach, or should I go with greenfield?" when trying to adopt React Native with an existing product, it's hard to feel certain in your decision. In late 2018 and 2019, I worked on two teams simultaneously that took different approaches. I will present our own justifications for each approach, what issues we encountered unique to each decision, and the outcomes we had. I'll also present a decision making framework to help inform future decisions of "greenfield vs brownfield".