Too Long; Didn't Read
The most important part is to add meaningful tests in your project. Don’t feel pressured to apply TDD in your work environment just because “that’s what the cool kids are doing” There is no such thing. The term Unit Test varies a lot between authors. Do not test implementation, test behavior or test behavior for every new class or function you add in the project. They can be refactored, removed, moved, moved etc. If you write a lot of details for implementation changes, test details are important.