Last year, I tracked every purchase I made under £10. Coffee here, a magazine there, a random kitchen gadget from the reduced aisle. By December, those "tiny" spends added up to just over £2,400. That number genuinely shocked me. It was more than my annual energy bill. That's when I built my own spending decision framework to stop impulse spending — and it starts with a single question.
What Is the 10 Pound Rule?
The rule is embarrassingly simple. Before I buy anything that isn't a genuine necessity, I ask myself:
"Would I rather have this thing, or £10 in my savings?"
That's it. No spreadsheet. No complicated formula. Just a moment of honest comparison.
The magic number doesn't have to be £10 — it's just what works for me. The point is to create a brief pause between the impulse and the transaction. Behavioural economists call this a "friction point." I call it not buying another candle I don't need.
Here's why it works: most small purchases aren't decisions at all. They're reflexes. You see it, you tap your card, you move on. The 10 Pound Rule forces a micro-decision, and that's often enough to break the pattern.
How I Actually Use It Day to Day
I'm not pretending I apply this to every 80p banana. This is specifically for discretionary spending — the stuff that's nice to have but won't ruin your life if you skip it.
A few real examples from the past few months:
- £4 coffee on the way to work: I asked myself the question. The answer was almost always "I'd rather have the £10." So now I make coffee at home five days a week and buy one on Fridays as a treat. That saves me roughly £70 a month.
- £8 true crime paperback at the train station: I wanted something to read. But I had three unread books at home. I put it back. The £10 won.
- £6 street food at a Saturday market: I was out with friends, it smelled incredible, and I genuinely wanted it. The food won. No guilt. The rule isn't about deprivation — it's about awareness.
The key is that you don't have to say no every time. You just have to choose each time. That shift from autopilot to intentional is where the savings come from.
Making Budgeting Small Purchases Automatic
After a few weeks of using the rule, I noticed patterns. I was spending the most on weekday lunches, impulse Amazon orders, and random bits from Boots.
So I set up a simple system to make budgeting small purchases easier:
- I gave myself a weekly "fun money" allowance of £30. Anything discretionary comes out of this pot. When it's gone, it's gone until Monday.
- I moved that £30 into a separate pot using Monzo. Their pots feature makes this dead easy — I can see exactly what's left for the week without checking a spreadsheet.
- I set up a round-up rule with Plum. Every time I do spend, the spare change gets swept into savings automatically. So even the purchases I make contribute something to my goals.
Between the 10 Pound Rule and these automations, I'm now saving about £150 more per month than I was before — and I genuinely don't feel like I'm missing out on anything.
Why Willpower Alone Doesn't Work
I tried the "just stop spending" approach before. Multiple times. It lasted about a week each time. The problem with relying on willpower is that it's a finite resource. By the end of a long workday, the part of your brain that says "you don't need that" is exhausted.
That's why the 10 Pound Rule works where pure discipline fails. It doesn't require willpower — it requires a two-second comparison. And the comparison almost always has a clear winner because, deep down, most of us know whether something is worth it or not. We just don't give ourselves the space to think about it.
If you want to go further, tracking apps can show you the patterns you can't see yourself. Emma is particularly good at categorising small, frequent purchases and showing you totals by category — which can be a proper eye-opener.
What to Do With the Money You Save
Here's the bit that makes this sustainable: you need to see the savings. If the money just sits in your current account and quietly gets spent elsewhere, the rule loses its punch.
I move my saved money into a savings account with Marcus by Goldman Sachs, which currently offers a competitive easy-access rate. Every time I skip a purchase using the rule, I mentally add it to a running total. At the end of the month, I transfer that amount.
Some months it's £80. Some months it's £200. Either way, watching that number grow is more satisfying than any impulse buy has ever been.
Start Today — Here's How
You don't need an app, a course, or a financial adviser to try this. Here's the practical version:
- Pick your number. £10 is mine. Yours might be £5 or £20. Choose what feels meaningful but not extreme.
- Use the question. Before any non-essential purchase, ask: "Would I rather have this, or [my number] in savings?"
- Don't aim for perfection. Say yes to things that genuinely bring you joy. The goal is to catch the mindless ones.
- Track roughly. Even a note on your phone with a running tally helps. After a month, add it up.
- Automate what you can. Set up a spending pot, round-ups, or a weekly transfer so the savings happen without you thinking about it.
The 10 Pound Rule won't transform your finances overnight. But those small purchases you barely remember making? They're costing you more than you think. And the fix is one honest question away.
Free tool: Use our Subscription & Direct Debit Audit spreadsheet (free) to find out exactly where your money goes each month. See all our UK finance tools.
Try the 10 Pound Rule for one week. Just seven days. Then check your bank statement and compare it to the week before. I'd love to hear how it goes — drop me a comment below or find me on social media.