I dont think it's as simple as that, after all there are book written about task management.

When "something" comes up, it's not always clear to me whether it's urgent or not, important or not. Getting it out into a list frees my mental capacity.

For example, I got a reminder to renew my passport yesterday. Not urgent, but important. Goes onto a list. I'll eventually prioritize and schedule it in my weekly review.

The key (for me) it aggressively devote attention to pruning these lists.

Breadth is not the issue, depth is. Nor there is much that I can reduce horizontally. At work, two or three open tickets + some blocked work in the "back burner" can already trigger the problem; on personal side, there's even more stuff that I need to keep track of, and take care of in parallel.

Those few "active" items and some more "standby" items are easy to list and read by themselves, but unexpanded, they're also non-actionable. And what I learned is, trying to expand even a few of them more than one level down quickly becomes overwhelming, and creates big overhead - as I work on one thing, the task breakdowns for the rest go stale, requiring additional effort to fix them. It surprised me just how fast this happens (and how quickly it leads me to stop looking at my own plans).

Related and perhaps extreme example that taught me much is when I took a medium-sized ticket that seemed perfectly doable in two to three work-weeks, and attempted to break it down all the way to actionable TODOs no larger than 2 to 4 hours worth of work. I wanted to see if this would streamline my work and allow me to make a more precise time estimate for the whole ticket.

I probably spent a day or two on the breakdown itself, complete with estimates and dependency links for every item - starting Z requires X and Y to be done, Y is done when A and B are done, etc. Standard project management stuff - lets you compute critical path and prioritize accordingly, and even draw a Gantt chart. My 3-week project ended up having some 150 tasks in it. Initially it looked great, but just a day or two into actual work, I found myself redoing large parts of the breakdown. Every two or three ticked-off tasks, the newly-gained knowledge made it apparent some task dependencies were to too strict, or entirely unnecessary. Large subtrees had to be split, shifted around or deleted, or had to have their estimates adjusted, all while new actionable tasks had to be added (and broken down). And that doesn't even includes the time spent readjusting the list after being pre-empted by some unrelated, critical-priority tasks.

All that planning quickly became a huge maintenance overhead. I only ever started making progress on the project itself when I stopped paying attention to my lists. That experience has taught me to stop breakdowns much earlier, and to stop eagerly breaking everything down to the same level - however good estimates I got this way, they weren't even needed for anything, and at the same time, they were constantly invalidated by added re-planning overhead.

These days, I don't break down work ahead of time beyond what's apparent and useful at the moment. I went from ahead-of-time to just-in-time.

Another factor is, it seems I'm really bad at the whole separation of planning and execution stages. My mind doesn't work that way, and can't stay in "execute this list one item at a time" mode for very long.