It's not a good idea to rewrite working code from scratch. But I've found starting a greenfield project next door to working code often works well.
Not every new feature needs to go in an existing repository. Sometimes it makes perfect sense to implement the new functionality in a separate executable and artifact that doesn't carry along all the technical debt of the old project.
Not every new feature needs to go in an existing repository. Sometimes it makes perfect sense to implement the new functionality in a separate executable and artifact that doesn't carry along all the technical debt of the old project.