I think this works great for things that can be easily scheduled with a start and end time/date: doctor’s appointments, tasks, step-by-step projects. Any time there is an established set of rules and methodologies. However, other things such as “write first chapter of my novel”, are easy to put off even if they are scheduled. I tend to ignore the schedule when it comes to things that require more heavy-duty creative thinking done in isolation. In my experience, it could take two hours, or a week depending on my mental state, energy level, or blocks. It’s very difficult to schedule that. This is why writers miss their book deadlines (George R.R. Martin comes to mind).