I think it's worth mentioning the Cynefin model here [1]. Both approaches can work, getting requirements up front can be the right approach for a well-know doma

I think it's worth mentioning the Cynefin model here [1]. Both approaches can work, getting requirements up front can be the right approach for a well-know domain, but often times it's better to treat requirements analysis as a discovery that is ongoing during development. For the latter case, classic project management simply leads to failure and it needs iterative development with tight feedback loops. [1] https://en.wikipedia.org/wiki/Cynefin_framework https://en.wikipedia.org/wiki/Cynefin_framework