Writing it down at the time

There is a category of fact that no receipt ever carries and no system can recover: who the meeting was with, which job the materials went to, whether the journey was for the client or the shops. It exists in one place, briefly, and then it doesn’t.

A note written at the time is not virtuous. It is simply the only kind of note that can be made while the information still exists, and that is a mechanical distinction rather than a moral one.

Why later doesn’t work

The fact isn’t fading — your access to it is. You could name every purpose behind last Tuesday’s spending. Last February’s, you can name perhaps a third, and you cannot tell which third. That’s the uncomfortable part: recall doesn’t announce its own failures. A reconstructed reason feels exactly like a remembered one.

Reconstruction fills gaps with the typical rather than the actual. Asked what a mid-March hardware purchase was for, you supply what you usually buy there. It’s a reasonable inference and it’s wrong some proportion of the time, with no signal attached.

Confidence goes up as accuracy goes down. Details get smoothed into a tidier story on each retelling. A note made months later is often more definite than one made on the day, which is the reverse of what its reliability warrants.

None of this is a character flaw and none of it is fixable with effort. It’s how memory for undistinguished events works, and receipts are the most undistinguished events there are.

What a note has to contain

Short. Three or four words does it, because you are not writing a description of the transaction — the receipt already has the amount, the vendor and the date. You are supplying the one field it lacks.

Who or what it was for. “Kitchen job, Hollis Road.” “Client lunch, Fenwick.” “Studio monitor cable.”

Which of two plausible purposes, where it’s ambiguous. A supermarket receipt might be office supplies or lunch. The note’s job is to pick.

Anything that won’t be obvious from the amount. That the total covers two jobs. That it’s a deposit against something larger. That a second person was present. That it was a replacement for something that failed.

That’s the whole content. The overwhelming failure is not writing too little, it’s writing nothing.

Where the note lives

Any of these works. What matters is picking one and not deliberating at capture time — the half-second of deliberation is what kills the habit, as in why batch entry fails.

On the paper, with a pen. Oldest and still among the best. One caveat specific to receipts: on a thermal slip, write on the back or the margin. Pressure and friction can mark the coated side, and the coating is where the image is — why thermal receipts fade covers why that surface is fragile.

In the filename, at capture. Best option for anything captured digitally, because a filename is the most copy-resistant metadata a file has. See what happens to metadata for why app tags and notes fields are a weaker place to put it.

In a running list. A single text file or notebook, one line per spend, date first. Surprisingly effective, because it needs no filing and no matching — you just append. It works especially well for spends where the receipt is elsewhere or nonexistent.

Spoken, if that’s the only one you’ll do. A voice note beats an unwritten note by an infinite margin. The requirement is that it gets transcribed at the weekly pass, or you’ve just moved the problem into a format that’s harder to search.

Keep or bin

KEEP OR BIN — notes and the things that
              look like notes

  · Three words written at the till
                    → KEEP. The only version of this
                      fact that will ever exist.

  · A running dated list of purposes
                    → KEEP. No filing, no matching,
                      appends in seconds.

  · Calendar entry naming the client on the
    same date
                    → KEEP. A contemporaneous note you
                      didn't know you were making.

  · A description worked out from a
    statement line months later
                    → NOT A RECORD. An inference.
                      Label it as one and keep it
                      anyway — labelled is fine.

  · A note in an app's own tag or comment
    field
                    → FRAGILE. Fine as a working aid;
                      it won't survive leaving the app.

  · Writing hard on the printed face of a
    thermal slip
                    → BIN the habit. Use the back.

  · Whether a self-made note carries any
    weight for a filing obligation
                    → ASK LOCALLY. Substantiation
                      requirements vary by
                      jurisdiction and record type.

The sources you’re already generating

Worth knowing, because it substantially reduces how much noting you need to do: several contemporaneous records of purpose already exist without any effort from you.

Your calendar is the strongest. Entries were written before the fact, by you, for a reason unrelated to recordkeeping. A meeting entry on the date of a restaurant spend is better evidence of purpose than a note you wrote afterwards.

Your correspondence. An email agreeing to a job, a message confirming a site visit.

Your photographs. Dated images of a job in progress, a delivery, a room mid-work.

These are why a reconstruction can partly succeed at all — see reconstructing a year you didn’t record. The practical implication runs the other way too: if you keep a reasonably specific calendar, you are already producing the reason field for a large share of your spending, and your notes only need to cover what the calendar doesn’t explain.

The awkward cases

Cash. No statement line, no descriptor, nothing but the slip. If the slip goes, the transaction leaves no trace at all, which makes the note the only thing between a cash spend and nonexistence.

Spends with no receipt. A parking meter, a market stall, a tip. There is nothing to annotate, so the note is the record — which is precisely the situation where a running list earns its keep. Whether such a note is acceptable for any purpose is emphatically not a question this site answers.

Regular, identical spends. The same supplier, the same amount, every month. Individually annotating these is pointless; a single line covering the arrangement does more, and it’s the case for treating recurring charges as a class rather than as transactions — recurring charges leave the thinnest trail.

What this doesn’t settle

Whether a note you wrote yourself is acceptable evidence of anything. Whether contemporaneous records are required, encouraged, or irrelevant where you are. Whether a note can substitute for a missing receipt. What form any of it must take.

Those vary by jurisdiction and by what the record is for, and your tax authority or adviser answers them. The claim this page makes is narrower and holds regardless of any rule: three words at the till cost eight seconds, and there is no later point at which those three words can be obtained.