I am only a few days in and the more I use subtasks the worse they seem to become as they duplicate many of the same things in the list and change the useful ones they had.
Also a task of morning routine at first had a great breakdown in the sub tasks but I realised I needed a different task for each day of the week to cater for weekly activities that started at different times so on recreating my morning routine all the subtasks were different from the original ones and many were duplicate meaning lots of manual work to get going.