A Sunday with no plan
The experiment was simple. One Sunday a month with nothing arranged, nothing bought, nowhere to be, and no list. I have now done seven of them and I can report that four were wonderful, two were flat, and one was among the worst days I have had this year.
The bad one
I want to start there, because every essay about unstructured time skips it. The bad one was in May. I woke with no plan, drifted until eleven, could not settle on anything, felt the day beginning to be wasted, and then spent the afternoon in a low-grade panic of unproductivity, doing nothing and enjoying none of it. By six I was in a temper. This is the failure mode nobody mentions: an empty day and a mind still running on the working week's logic will spend the day marking itself absent.
What made the good ones good
Two things, as far as I can tell.
The first is that the good ones had one anchor - not a plan, but a fixed point somewhere in the middle. A long walk, a meal that needed three hours, a bath at four in the afternoon. Something unhurried and physical that the rest of the day could arrange itself around. The bad Sunday had no anchor at all and just fell over.
The second is that the good ones had a boring stretch in them and I let it be boring. Boredom on an unplanned day is not the day failing. It is the point at which the day stops being a smaller version of the week. About forty minutes past it, something usually happens - I pick up an instrument I do not play, or start a job in the garden I had not thought about, or fall asleep in a chair in the afternoon like a much older man.
The tolerable amount of boredom is roughly forty minutes, and almost nobody now gets to find that out, because the phone arrives at minute two.
Rules I did not intend to have
No shops, which started as an accident and turned out to be the most important one. A trip to a shop is a task and a task is a plan.
No screens until the evening. Not for purity - because a screen is where the day goes if I let it, and then Sunday evening arrives with nothing in it to remember.
And no announcing it. The first two I told people about, and telling people made it a project with a result to report. Now I just do not arrange anything for one Sunday and say nothing about it, apart from here, which I accept is a contradiction.