The block is on the calendar. Deep work, 9:00 to 10:30. At 9:03 you open the document and read a paragraph. At 9:06 you remember an email you meant to send, and it takes ninety seconds, and then rather longer than ninety seconds. By the time you look up properly it is 10:15, and the session has happened around you instead of with you.
That is not a discipline problem. It is a design problem. A deep work block has a beginning, a middle and an end, and most of us plan only the middle, and only vaguely. What follows is a single session, start to finish: how to set it up so the first twenty minutes aren't wasted, how to hold the line when the day pushes back, and how to close it so the next one starts faster.
Why ninety minutes is the right container
The practical reason to use ninety minutes is that it has a shape you can hold in your head. It is long enough to get past the awkward opening stretch, when your attention is still catching up with the task, and short enough that you can see the end of it from the beginning. That visibility matters. Two hours invites a slow start and a wandering middle; an hour often barely survives the catching-up phase.
Treat the ninety minutes as a container, not a promise of peak concentration. Some of it will be slow. You will reread a sentence three times. You will stare at the screen and think about lunch. That is part of the cost of doing something difficult, not evidence that the block failed. What you are protecting is a stretch of attention, not a feeling of flow.
If ninety minutes feels out of reach right now, set the block at forty-five and build up over a few weeks. The structure below doesn't change; only the length does.
The ten-minute setup
The ten minutes before you start do more for the session than any app will. Do them the day before if you can, or first thing in the morning before anything else gets a claim on you.
Name the deliverable, not the topic
"Draft section 3 of the pricing comparison, about 600 words, messy is fine" is a deliverable. "Work on the report" is a topic, and it will quietly turn into reading and rearranging — which feels like work and rarely produces anything you'd send to a colleague. A deliverable has an edge to it. You can tell, at 10:30, whether you reached it.
Stage the room and the file
Water, headphones, notebook, the document open, the reference material open at the right page. Anything you would have to get up for is a door out of the block, and you will walk through it at the first difficult moment. Charge the laptop the night before. Print the thing you keep scrolling back to find.
Write an exit note
Before you type a single useful word, spend thirty seconds writing down where you are and what the next physical action is. Something like:
Page 4, mid-paragraph on onboarding times. Next: pull the two figures from the finance sheet and write the comparison sentence.
If the session gets cut short — and sometimes it will — that note gets you back in without half an hour of re-reading.
Defending the block
The two danger zones are the first five minutes and the middle. The first five are where a quick check becomes a twenty-minute detour. The middle is where restlessness arrives dressed up as a good reason to look something up.
- Notifications off at the device level. Silencing the sound but leaving badges on the screen isn't much of a wall.
- A capture pad beside the keyboard. Every stray thought — reply to Sam, buy stamps, check that word — goes on paper, not into a new tab.
- One sentence ready for colleagues. "I'm heads-down until half ten, can I find you after?" Say it before the block starts, not when someone is already standing at your desk.
- Phone in another room, or in a drawer. Face down on the desk still lights up.
- One window. Close everything you don't need, including the tabs you are "keeping open for later".
- The end time in sight. A sticky note reading 10:30 does more than you would expect when the session gets uncomfortable.
It also helps to place the block where your attention is naturally decent. For most people that is not immediately after a morning of back-to-back calls, and not the half hour before lunch.
When the session goes sideways
The mid-block wobble
Somewhere around minute forty, the actual work stops feeling urgent and everything else starts to. This is ordinary; it shows up in almost every long session. The rule is simple: do not check anything. Stand up, walk to the window or the kitchen, drink some water, sit back down and read your exit note. Ninety seconds of movement usually resets more than ten minutes of scrolling.
When you are genuinely stuck
Stuck is different from restless. Write down, in one sentence, what you don't know. Then shrink the task: if the paragraph won't come, write the ugliest possible version of it, bullet points allowed. If the thinking still won't move after ten minutes, switch to a defined sub-task inside the same project — gathering, formatting, checking figures — rather than leaving the block altogether. You keep the thread even on the days you can't push it forward.
When the interruption can't be refused
A client calls, a child needs something, a colleague has a real emergency. Take the interruption, deal with it, then spend sixty seconds re-reading the last paragraph you wrote before you restart. Do not restart by checking email. That is a second interruption wearing the costume of a reward.
The ten-minute review
Stop producing about ten minutes before the end. It feels wasteful; it isn't. The review is what turns a single session into a practice you can repeat, and it is the part nearly everyone skips.
- Write where you stopped and the exact next action. Two lines is plenty.
- Compare what you said you would deliver with what now exists. Be plain about the gap — "got 400 words, not 600" is a useful note and not a confession.
- Name the one thing that cost you time: a missing file, a decision you hadn't made, a vague objective, a meeting that ran over.
- Fix one of those for tomorrow. One. Not a new system, not five resolutions.
- Close the files, tabs and windows for this project. Leave the desk as you would want to find it.
Keep those notes in one place, on paper or in a single document. After a couple of weeks you will start seeing the same obstacle repeating, and that is where the real gains are — not in a better app, but in removing the same friction twice.
Start with one block this week
There is no need to rebuild your week. Pick one morning, put ninety minutes in the calendar, and write the deliverable the night before in a single sentence. Run the ten-minute setup, defend the middle as well as you can, and do the review even if the session felt mediocre — especially then, because that is when the notes are most useful.
Then do it again the same week if possible, at the same time. Two ordinary blocks are worth more than one excellent block followed by nothing for a fortnight.
One last note, since focus is physical as well as mental: if long stretches at the desk leave you tense, headachy or stiff, shorten the block rather than pushing through, and take a real break between sessions. Symptoms that persist are worth raising with a doctor rather than working around.
Photo: wal_172619 / Pixabay