In January you wrote $400 next to groceries. In March you spent $612 and called yourself undisciplined. You were not. The $400 was never your grocery number — it was your hope for a grocery number.
The number you wish vs the number you are
Take three complete months of real spending and average them. That is your number. A budget built on it survives contact with a normal month, because it already contains your normal month.
| Category | Wished | Real 3-month average |
|---|---|---|
| Groceries | $400 | $580 |
| Eating out | $100 | $245 |
| Transport | $120 | $138 |
Where month three goes wrong
January and February hold because the year starts with attention. March is when attention runs out and the real number takes over. A budget set at the real number has no month three.
A budget is a measurement you commit to, not a wish you make.
Open your last three months of statements tonight. Average one category — just one — and replace the wish with the average. That category will never surprise you again.