This is a quote from a presentation by Diego Aguiar at SymfonyCon that I saw from [a tweet from SymfonyCasts](https://twitter.com/SymfonyCasts/status/1593551105471938560?t=A8wnRUa0tLbb2q5qLhcQnA).
I haven't seen the rest of the presentation, but I liked this quote and the idea of continuously improving a codebase using automated tests.
The talk was titled "Advanced Test Driven Development" so I assume that it was focused on ensuring that new functionality also has accompanying tests but it could also apply to existing code.
A lot of existing code that I've worked on wasn't covered by tests, so going back and writing tests for that code would be beneficial too - even if it's only one test a day. It would help to prevent and uncover existing bugs, enable the code to be refactored and changed without introducing regressions, and make the codebase more maintainable.
