In my experience (startup product development), product requirements and constraints are constantly shifting in order to support new use cases. In my practice, that has translated into only formalizing specifications after the fundamental needs of a system are set in stone, which is usually after release. When I’ve worked on contract-based projects, it’s been much easier to formalize beforehand, but I suspect most developers on HN are involved in active product development.
Thats true, but at least before implementation, the behaviour to be implemented should be known to some extent. UML Statecharts remain a good method to document behaviour.
