There’s an interesting ‘law’ of time management that says something we all probably intuitively understand:

“Work expands so as to fill the time available for it’s completion.”  ~Parkinson’s law.

A bit formal, but basically, work is like a fluid and will fill whatever crannies you allow it to. This can be bad if you consider yourself as a swimmer… you really don’t want that stuff in your lungs.  As anyone who’s had work take over their life knows, the metaphor is apt. If you give yourself an hour do wash the dishes, it’ll take you an hour. Reports, marking, reading, pretty much anything can be applied to this.  Well, most things, anyway.

Some things just take a certain amount of time and if you’re doing them the way they ‘should’ be done, they’ll be done right in a set amount of time.

Roasting a chicken, driving an intercity bus or train etc. Not much scope for monkeying with time in these cases.

Anyway, let’s get started.  Time boxing is artificially constraining the time allowed for a particular task. (…and no, hundreds of miles of driving travel should not be timeboxed, at least beyond legal limits… )

1. Get a kitchen timer, or set one on your phone. 1, 5, 10 or 15 minutes
2. Get ready to start your task…
3. …and go!

As the timer winds down, your task will speed towards completion like a greyhound chasing a rabbit! In a way, by chasing the time, you’re adding an element of play to your work and there’s something about that little bit of play that focuses the mind and sharpens your skills. Things get done.
If there are a few things to do, set 5 or 10 min time boxes. Longer than 25 min and they don’t seem to work as well. Three 10 min boxes are going to be way more effective than 30min. I personally never use anything longer than 20 min. I find beyond that, I might as well not be time boxing.
Now, I’ve known that constraining time for things somehow makes stuff get done better and feel more fun for about 20 years, but there’s a guy who goes by the moniker Kazumoto, who really brought it to life for me. On his legendary site, AJATT, which stands for All Japanese All The Time, he is constantly looking at the value of constraints and other productivity techniques with the aim of helping people learn languages. Originally, it was his blog for talking about how he learned Japanese to adult level fluency in 18 months. No small feat!. The guy is a legend. I’ve been a fairly competent Japanese speaker for going on ten years now and I can’t even touch the guy’s level.
Anyway, one of the things I like most about his site, and which I think explains the fun and usefulness of timeboxing is the formula for making things ‘fun’ that he uses.
U = EV / ΓD
• U = Utility, i.e. fun. The idea is that humans always make the choice they believe maximizes U. IIRC, humans always want and choose to do the thing that has the highest U.
• E = Expectancy. Your confidence in your ability to complete the task.
• V = Value, i.e. importance of the task.
• Γ = Distractions.
• D = Deadline, delay. How much time you have to do the task.

It’s called the Temporal Motivation Theory equation, created by Piers Steel of the University of Calgary. One of the things I really liked about the AJATT site was Kaz’s inclination to dig deep into personal development of the more scientific sort. No airy-fairy fluffy stuff for him, just good, solid, experience-based info.
If you’ve got a few hours, his site is a ‘totally fantastic’ read. There are probably days worth of worthwhile reading there. Honestly. And it’s all packaged in his distinctive writing style.
One of the other things I like about timeboxing is your ability to just get a ton of things done now, as in whenever in the day you feel like starting. There’s no waiting for the hour or until something… it’s just set the timer and go. I’ve used this pretty successfully in the classroom and with my tuition students as well. There really is something to Prof. Steel’s equation.
Another time boxing style I should mention comes in the form of the Pomodoro (tomato in Italian) with, probably, Prof. Barbara Oakley popularizing the technique to enhance study efficacy. It’s a 25 min timer followed by a 5 or 10 min break. If you only have an hour to work, making that break longer in the middle of your hour will be more useful than having a break just before the end of the hour. Perhaps obvious, but I’ve had people plan their Pomodoro with two 25:5s back to back, leaving the second break just before you stop anyway. The suggestion is that when you are taking a break, you are doing something completely different to the study, like playing an instrument, doing burpees or whirling your toddler about in the living room.
I’ve used these myself for years and have taught them to many students who have found them really useful. They’re like, mad useful. It really rationalizes your use of time increments, bringing an intensity you just wouldn’t be able to create if you didn’t have the timer.

***What could you get done with some timeboxing that wouldn’t otherwise get done? Set a timer, 10-min, what are you going to do?!?