This might run against using time intentionally, but I find myself wanting to block off "Dedicated Sessions" where the task is bigger or more-abstract than a discreet task might be able to cover.

I regularly create a tasks like "Scheduling UX" where I know that I need to chip away at user experience for a particular feature I'm designing. The time block I set should add to the "total time spent" on "Scheduling UX" until it's been completed. I might "complete" a single session (i.e. I successfully focused on Scheduling UX for an hour, but I have not yet completed Scheduling UX).

Then when a particular project has been completed, I can mark that macro-project complete and see how many hours I spent on it.

Even better would be to allow an occasional discreet task be assigned to a particular dedicated session task. Something like "Populate with fake data for eng review". The time spent would still contribute to the overall time spent on that work.

Last thought, it might be a unique need for creative/design oriented use-cases, where deeming something done is somewhat unknown until you know it's done. I might think I know what I'll do for Scheduling UX in my head, but when I get it all out and prototype it, I realize something new and go back to the drawing board.