Breaking huge tasks up is obviously necessary to make any real progress, regardless of whether you're trying to estimate anything - even if it was my job as an

Breaking huge tasks up is obviously necessary to make any real progress, regardless of whether you're trying to estimate anything - even if it was my job as an individual to do the whole huge task myself I'd want it in digestible chunks that I could feel I was making progress with, but more realistically it's going to be split between several developers anyway. Determining how to do that decomposition into subtasks that are genuinely independent (and ideally can be worked on in parallel) is obviously a key challenge of large-scale software development, and there almost never no "right" answers as to the best way of doing so. Interestingly if I've noticed anything is that once you split a huge task up in little ones and give each of those estimates, the total is often far bigger than you might have considered for the original task. And is more likely to be closer to the mark.