My intuition based on 20 years of working on large-ish projects, is that code reviews are always helpful, and mandatory unit tests waste a lot of time and effor

My intuition based on 20 years of working on large-ish projects, is that code reviews are always helpful, and mandatory unit tests waste a lot of time and effort, at least for statically typed code. I don't have much experience with dynamic languages. This doesn't mean don't write any unit tests, but to use discretion instead of enforcing coverage. So, it's perfectly reasonable for a code reviewer to say, "a unit test could be really helpful here."