Three projects in a day and I lose half an hour at every handover, is that normal or am I doing switching badly?

Some of it is intrinsic and the structural fix is the big win: change the size of the block, not the quality of the switch.

If a switch costs thirty minutes, then three switches a day cost ninety minutes regardless of how good you get at switching. But three switches a week cost the same thirty minutes each and you pay it three times instead of fifteen. The cost is per switch, so the lever is the number of switches, not the price of one.

What that looks like in practice:

A day per project where you can get it. Monday and Thursday on one, Tuesday on another, and so on. The cost drops by most of itself immediately.

Half days if a full day is impossible. Still a large improvement over three switches.

Never more than two switches a day. This is the line worth defending even when everything else slips.

The objection is always that people are waiting and cannot wait a day. Usually much less true than it feels: most of what feels urgent is a message that needs a two-minute reply rather than a context switch into the project. Answering a question about a project is not the same as working on it, and conflating those two is what produces a day of five switches.

So: keep a short window for replies across everything, and defend the blocks for actual work.

The habit that halved my re-entry cost, and it costs about ninety seconds: write the landing note before you leave, not when you arrive.

Before switching away, write down three things where you will see them next time:

1. What I was doing in one sentence
2. The exact next action: not the goal, the literal next thing to type or open
3. Anything I was holding in my head that is not written anywhere: the thing I was worried about, the idea I had not tested, the question I was going to ask someone

That third one is where most of the thirty minutes goes. Re-opening files is fast; reconstructing the thought you were mid-way through is slow, and it is the part that is nowhere on disk.

Why before rather than after: you have the context loaded right now and it costs you nothing. Tomorrow you have to rebuild it in order to write it down, which is the expense you are trying to avoid.

Two details that make it work:

Same place every time, per project. Top of a file, a note, whatever: the point is not hunting for it.

Write it even when you think you will remember. You will remember for about four hours. The note is for the version of you who has since done two other projects.

Two things worth knowing beyond the structural fix.

Your thirty minutes may be more than switching. Time it honestly for a few days and split it: how much is genuinely reloading the project, and how much is the drift that happens at any transition: the coffee, the inbox, the five minutes on something else. Those are different problems with different fixes, and most people find the second is bigger than they expect. Switching gets blamed for the whole transition.

The residue is real and it is worse when you leave things unfinished mid-thought. Stopping at a natural boundary, a completed piece, a passing test: costs much less on both ends than stopping in the middle. Where you have a choice, spend five extra minutes finishing the unit rather than stopping on the hour.

And a caution about the opposite failure: some people respond to this by refusing to switch at all and letting two of the three projects rot for a fortnight. That has its own cost, paid by other people, and it comes back as a much larger interruption when something goes wrong.

The realistic target is not zero switching. It is fewer, larger blocks, with a note at each exit: which between them will get you most of that hour back without changing your commitments.