- As part of original development (red/green/refactor)
- When suggested by a code reviewer
- When we've noticed a design pain-point
- When making another change, if the refactoring is low impact, i.e. typically not affecting any other files.
If it affects the public API, I generally like to make the refactoring a single source code commit which doesn't change behaviour (and then build new behaviour into another commit). If it affects other projects too, there needs to be consensus over it and I would want to get permission to change their code to go in the same refactoring commit.
