The ten o'clock boss, the manager who is you, on call, time zones, the freelancer, night thinking and the family chat

Most readers can stop at chapter 21. This one is for the situations where the window needs a gate, or where the class is harder to teach.

The boss who sends at ten and says "no need to reply". Take her at her word. She's told you the window is fine. If she sends at ten and does expect a reply, and says so, then chapter 7's guess has been checked and the answer was yes. Ask what specifically she needs after six, because "everything" is rarely true, and most of the time it comes down to one kind of thing, which becomes the other door. If it really is everything, and it's enforced with consequences, that's a job with an on-call duty that isn't paid as one, and ACAS is the place to ask what's reasonable. This book can't teach a class that's decided not to learn.

The manager who is you. If you're the one sending at ten, you're the one teaching. Everything in chapter 13 runs downhill from you faster than from anyone. Derks' study found that supervisors' expectations were what turned evening phone use into interference for the people under them. So write the emails at ten if that's when you write them, and schedule them to send at eight in the morning, which every mail program can do. Put the note from chapter 18 on anything you can't hold. And say the window out loud to your team, on their behalf, because they're less able to say it to you.

On call. If your job has a rota, the rota is the other door and it's already built. The window applies to everything that isn't the rota. What tends to go wrong is that the on-call channel and the ordinary channel are the same inbox, so that being on call for emergencies means being on call for everything. Separate them. The pager, the on-call phone, the emergency thread, whatever it is, stays on. Ordinary mail goes on the schedule. When you're not on the rota, you're not on the rota, and that includes the ordinary channel.

Time zones. If half your team is eight hours behind, their afternoon is your evening, and the window can't be nine to six without cutting them off. Move the window, don't widen it. Ten to seven, or eight to five with a fixed hour at nine in the evening on the days they need it. What the window can't be is "whenever they're awake", because then it's the whole day and night. The team abroad learns your hours the way Priya did, and they've got their own window to think about.

The freelancer whose clients expect it. Clients are a class you can teach, and the line in chapter 18 is your terms of business. Put the window in your proposals and your signature. The client who insists on evening replies is telling you what the job costs, and you can price it, or decline it. What you can't do is give it away by default and resent it. The earlier book Your turn to text is about the friend you keep meaning to reply to. The client is the opposite. The client you reply to too fast.

Night thinking. If your best ideas come at eleven, write them at eleven. Just don't send them at eleven. A draft saved, or a message scheduled for the morning, gets the thinking down without teaching anyone that eleven is a time you're available. The thinking was yours. The sending is the lesson.

The family chat. It isn't work, and it works the same way. The chat that expects an answer in minutes, the birthday planning that runs until midnight, the message left on read that becomes a small grievance. Cambier's nurses in chapter 8 were feeling pressure from personal messages, not work ones. The window can apply to any channel that's teaching you to watch it. Say so once, lightly, and answer in the morning. The family adjusts faster than the office.