Timeboxing, the time-management technique supposedly revered by millionaires and billionaires, does indeed have benefits. Similar to time blocking, timeboxing has you take items that might normally go on your to-do list and schedule them on your calendar instead. In this way, you plan out when you will do your tasks and thus decide in advance how you will use your time each day.
The difference between time blocking and timeboxing, however, is that timeboxing is specifically meant to limit how much time you spend on a task. With time blocking, the idea is to estimate reasonably how much time you need to finish a task. Have you ever heard of the trick where you set a timer for 10 minutes to do a task you hate, like clean the bathroom? The timer supposedly motivates you because it means the task will not drag on forever. You vow to get as far as you can in 10 minutes and then simply stop and not waste any more time on this task.
Timeboxing is like that. It's meant for tasks you do not want to spend much time doing, but you need to get done. In an office job, processing email is a good example. You don't want to spend a lot of time on it, but it needs to get done. But there are big problems with timeboxing that you need to know about before you use it.
Timeboxing Isn't Designed for All Tasks
If you heard about timeboxing in an article or video, the person explaining it may have skipped right over (or didn't know about) the fact that it's a terrible, horrible, no good, very bad system for many kinds of tasks, namely, the ones you need to do well.
For example, you wouldn't want to timebox writing, editing, and proofreading an application for a grant if you think you have a good shot at getting the money. Why? Because that's not the kind of work you should rush. You'd be better off allocating more time than you need for that task and breaking it into parts because that's a more effective way of making sure you write the best grant application you can. Plus when it comes to proofreading a very important document, it takes as long as it takes.
Some advocates of timeboxing have suggested the concept of a "soft" timebox, meaning the end time of some tasks is merely a suggestion and not a mandate. Perhaps you can make an exception here and there for when you wrap up your tasks, but then you aren't, in fact, following the timeboxing system at all, and it still doesn't account for tasks, like proofreading, that should take as much time as they require to complete well.
Timeboxing Must Be Used Selectively, Not Broadly
This point is related to the previous one, and it's for those of you in the TL;DR camp who perhaps glossed over an article about timeboxing, saw an image of a calendar totally blocked off to do all the day's tasks, and assumed that you should use timeboxing all day long to manage your work.
No, no, no, please don't do that! That's time blocking, not timeboxing.
Timeboxing should be used selectively, not broadly. It's not a good method to use all day long or even every day.
People Are Bad at Estimating How Long Tasks Will Take
Another hitch in the timeboxing system is that humans are absolute nincompoops when it comes to guessing how long their tasks will take. The so-called time planning fallacy, described by Daniel Kahneman and Amos Tversky in the late 1970s, used research on task planning to show just how consistently people underestimate how long their tasks will take, and it's just as applicable to individual tasks as group tasks.
So even if you think to yourself, "I'll timebox this task and estimate enough time for it to do a good job, get it done, and be efficient about it," the data suggest you probably won't. You're much more likely to cut yourself short.
Millionaires Might Timebox, But They Also Have Assistants
Any time someone tells me a trick that millionaires and billionaires do, you know what I think about? All the assistants and other workers who finish the job for them. The real secret of rich people's productivity often turns out to be that they delegate—in other words, someone else does the work. If you spend 30 minutes working on a tough problem and then hand it off to someone else to finish, you're benefitting as much from outsourcing as you are from timeboxing. If you don't have the resources to pay someone else to work for you, maybe don't measure yourself against those millionaires and billionaires too closely.
If you're going to use timeboxing, make sure you use it selectively on the right kinds of tasks and don't overuse it.
For more realistic productivity advice, how to take better breaks to boost your productivity and how to choose what to work on first.