I don't agree. Big refactors are _hard_. They usually require levels of sustained focus at multiple layers of abstraction, and its really easy to get exhausted/

I don't agree. Big refactors are _hard_. They usually require levels of sustained focus at multiple layers of abstraction, and its really easy to get exhausted/burnt out or be forced to switch gears in the middle. People learn by doing. And after a few such messes, the dev will learn how to do smaller refactors.