When a refactor cannot be done in an iterative fashion — there are some changes that are just too fundamental to be done in small pieces — then one approach is

When a refactor cannot be done in an iterative fashion — there are some changes that are just too fundamental to be done in small pieces — then one approach is to write a review guide, document what has changed and why, indicate to reviewers where the pain points are. One argument against gradual refractors is that they are often left half done when enthusiasm runs out. I’ve seem mloc sized code bases with multiple layers of half done refactors and migrations.