Comment by maccard

It's also the most valuable part of the entire article, and is true whether you're using waterfall, scrum, Extreme Programming, Kanban, or whatever. It's also the only thing that reliably works - the better you are at breaking down your work the better your estimates will be. As you said though, breaking down the work is oftentimes the largest part of the work because it requires _starting_ the work in the first place.