Francesco Cirillo, inventor of the Pomodoro technique, says break tasks into 25-minute increments.
Tony Schwartz, author of The Way We’re Working Isn’t Working, says you need a 90-minute working session to do great work on a high-intensity task.
So which is it? How much time do you really need?
It depends on the task, and it depends on you.
For tasks you dread, use the Pomodoro technique with a countdown timer. For some of you, this will be writing. For others, it will be editing. Some scenes may be harder to write than others. Pomodoro them.
But for tasks you love, the ones you’re eager to do, the ones where you may achieve flow, use a countup timer and shoot for 90 minutes. If you hit 45 and are tired, take a break.
You can plan for this. When you’re making your to-do list, divide the tasks into countdown tasks and countup tasks. Knowing which kind of timer to use when will help you stay on track and in flow. It will also help you schedule tasks into slots in your day when you have the necessary time available.
Adjust the amount of time you allow for a project not only by the expected time to completion, but by how long you can stick to it before you get sick of it and need a break.
Above all, you need to plan around what you can actually do. I have a couple of writer friends who can only write in 15-minute blocks because of health issues. They need to rest in between. But I write far better if I block off an hour or two and just go the whole time, with just a few breaks to stretch.
Know yourself well enough to know which method will work best for you and when. Sometimes that means experimenting with different durations and different times of day.