The Category I Had to Invent Was "I Don't Know Why I Bought This"

When I started categorising my spending I used the standard buckets — food, transport, housing, tools, entertainment. Within three weeks I had added one that no budgeting app offers, because I kept finding transactions I could not honestly place. I labelled it “unexplained,” and over six months it came to £1,847, which was more than I spent on groceries.

I want to be precise about what went in it, because it is not the same as impulse spending and calling it that would have let me off. An impulse purchase is one I decided to make quickly. These were purchases where, looking at the line a week later, I could not reconstruct a decision at all. A £34 cable. A £61 charge from a shop I remember visiting and not why. Three separate purchases of the same kind of drawing pen at three-week intervals.

The pens are the clearest example and the one that taught me the most. I did not need three. I bought the second because I could not find the first, and the third because I could not find either. So the actual cost was not £27 of pens; it was £27 of pens plus the fact that my studio has no system, and no budget category would ever have shown me that, because the pens are legitimately a work expense and would have sat quietly under supplies.

That is the thing the unexplained category does. It is not a category of purchases, it is a category of failures, and each one points at something structural. Sorting mine at the end of six months, roughly forty percent were replacement-because-I-lost-it. Twenty-five percent were bought while travelling or otherwise out of routine. Twenty percent were what I would call maintenance avoidance — buying something new rather than fixing or cleaning something I had. And the rest were genuinely mysterious.

The forty percent had one fix and it was not financial: a shallow drawer with a fixed place for six things I buy repeatedly. Cost me an afternoon. That category has essentially stopped, and I would not have found it through any amount of budgeting, because every individual purchase was defensible.

The travel one I have not solved and I am not sure it is solvable. Out of routine, I spend more and I decide worse, and the amounts are not large enough to be worth building a system around. I have accepted it as a known cost of being away, which is at least better than the previous state of being mildly surprised each time.

The maintenance-avoidance group is the one I would flag to anyone else, because it is the most invisible. Buying a new thing is a purchase and shows up. Failing to fix the old thing is not an event and shows up nowhere. In my case it was three items over six months, about £280, all of which I still own alongside the working replacement.

The method itself is simple and I would recommend it over more elaborate tracking: keep your normal categories, and add one for transactions you cannot explain. Do not try to be strict about the definition — if placing it took real effort, it goes in the unexplained pile. Then at the end, sort that pile by what went wrong rather than what was bought.

What I would not claim is that this saved me money in the short term. In the six months of tracking, my total spending was roughly flat. What it produced was four specific structural things to change, three of which cost nothing, and the effect of those has shown up in the year since rather than during the experiment.