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Analyse your spending: three questions before the categories
September shows €4,400 of spending, against €3,300 in an ordinary month. Taken alone, that figure does not say whether the household has changed its way of life or has just paid for the new school year, as it does every year.
The reading comes down to three questions, asked of at least twelve months of transactions. Which months come back heavy from one year to the next? How is spending spread around payday? How many categories and payees carry most of the total?
Income is read the same way, separately, and gives each month's balance once set beside spending.
The answers are facts drawn from your own transactions, with no score and no judgement. A heavy month is not a "bad" month: December often costs more than February, and that says nothing about how a household runs its accounts.
A single month tells you only its amount; the year around it tells you whether it is usual.
Seasonal expenses: the months that come back every year
In this guide, a month is seasonal when its spending is at least 30% above the monthly average of its own year, in at least two separate years. Once is a coincidence. Twice is a pattern.
The table follows a fictional household in 2025: €39,600 of spending over the year, €3,300 a month on average, and a threshold at €4,290. The amounts in this guide are made up for the example.
| Month | 2025 spending | 2025 monthly average | Ratio to the average | 130% threshold crossed in 2025 | Crossed in 2024 |
|---|---|---|---|---|---|
| January | €2,900 | €3,300 | 88% | No | No |
| February | €2,700 | €3,300 | 82% | No | No |
| March | €2,800 | €3,300 | 85% | No | No |
| April | €2,900 | €3,300 | 88% | No | No |
| May | €2,800 | €3,300 | 85% | No | No |
| June | €2,900 | €3,300 | 88% | No | No |
| July | €3,600 | €3,300 | 109% | No | No |
| August | €2,900 | €3,300 | 88% | No | No |
| September | €4,400 | €3,300 | 133% | Yes | Yes |
| October | €4,400 | €3,300 | 133% | Yes | No |
| November | €2,700 | €3,300 | 82% | No | No |
| December | €4,600 | €3,300 | 139% | Yes | Yes |
| Year | €39,600 | €3,300 | 100% | 3 months | 2 months |
September, October and December cross the threshold in 2025. September and December had already crossed it in 2024, so they are seasonal for this household. October had not. It stays a coincidence for now, and 2026 will tell whether it comes back.
September is not heavy by chance. According to the Caisse pour l'avenir des enfants (CAE), Luxembourg's family benefits fund, the school start allowance (allocation de rentrée scolaire, French-language page) is worth €115 per child over 6 and €235 per child over 12, paid automatically in August each year (page updated on 13 October 2022).
For a cross-border worker who owns a home in France, the 2026 taxes foncières, France's property tax, can be paid online until midnight on 20 October, with a bank direct debit from 26 October, according to impots.gouv.fr (in French). An annual bill like this weighs on October every year.
One heavy October is a coincidence; two heavy Octobers make a seasonal expense.
Spending habits within the month: the rhythm of the salary
In Luxembourg, the salary in money, as opposed to benefits in kind, is paid every month "at the latest on the last day of the calendar month concerned" (our translation), as the Inspection du travail et des mines sets out in its question and answer D4a9, a French-language page updated on 21 July 2020 that refers to Articles L.125-7 and L.221-1 of the Labour Code. Rent and the debits timed around the salary therefore often fall in the first days of the following month.
The rhythm is read in three bands, the 1st to the 10th, the 11th to the 20th and the 21st to the end of the month, along with the busiest day and the split across days of the week. The last band runs to as many as 11 days. Over an average month of 30.44 days, perfectly even spending would give about 32.9%, 32.9% and 34.3%. Each share is read against that baseline, not against a third.
| Band | Share if spending were even | Observed share | What it holds |
|---|---|---|---|
| 1st to 10th | 32.9% | 46% | Rent on the 1st, insurance, subscriptions, the big early-month shop |
| 11th to 20th | 32.9% | 28% | Groceries, fuel, outings |
| 21st to the end | 34.3% | 26% | Smaller shops, few purchases before payday |
The first band sits 13 points above its baseline, and the busiest day is the 1st, when the rent goes out. The third stays well below its own. Money leaves quickly after payday, then the pace slows. Across the week, the Saturday grocery run dominates, while the debits go out on fixed dates.
Each band is read against its own baseline, 32.9% or 34.3%, and the start of the month goes above its own as soon as rent follows the salary.
Where does my money go: the categories behind 80% of the total
How many categories, and how many payees, make up 80% of spending over the last twelve complete months? What share do the top five carry? The cumulative curve answers both. The 80% threshold is a reading aid, not a law of nature.
| Category | 12-month amount | Share | Cumulative share |
|---|---|---|---|
| Housing | €14,400 | 36.4% | 36.4% |
| Groceries | €6,000 | 15.2% | 51.5% |
| Transport | €4,800 | 12.1% | 63.6% |
| Taxes | €2,400 | 6.1% | 69.7% |
| Restaurants | €2,000 | 5.1% | 74.7% |
| Children and school | €1,800 | 4.5% | 79.3% |
| Leisure and holidays | €1,600 | 4.0% | 83.3% (80% crossed) |
| Health | €1,200 | 3.0% | 86.4% |
| Subscriptions | €1,000 | 2.5% | 88.9% |
| Clothing | €800 | 2.0% | 90.9% |
| Five other categories | €1,200 | 3.0% | 93.9% |
| Uncategorised | €2,400 | 6.1% | 100% |
| Total | €39,600 | 100% | 100% |
Seven categories out of fifteen make up 80% of the total. The top five carry 74.7%, and housing alone more than a third. On the payee side, the household reaches 80% with 14 payees out of 160.
The €2,400 with no category gets its own line, placed last whatever its size. Spending with no payee follows the same rule.
Seven categories out of fifteen make up 80% of this household's spending, and the "uncategorised" line stays visible instead of being spread across the others.
A lasting change: linking it to a life event
A seasonal month comes back on its date, then goes away. A lasting change settles in: a category rises or falls and stays there, whatever the season.
A category's usual level is the median of months −12 to −4, nine months in all, at least six of them with spending. The change is lasting when the last three complete months are all above 125% of the usual level, or all below 75%, with a gap of at least 30 units of the currency each month.
A fictional example: Restaurants has a usual level of €140, and the last three months show €205, €210 and €215, €210 on average. The upper threshold is €175, all three months are above it, and the smallest gap, €65, is more than 30. The change is lasting. What the figure cannot say is why.
A life event declared by the person puts a reason next to the figure: a move, a birth, a new job, retirement, a home purchase, an inheritance. Here, a new job in town three months ago would explain the lunches. The event explains the change but alters nothing by itself. A separation, a bereavement or a health event belong to private life: never detected, never sent to an AI, never shown in a shared space.
Three months in a row far from the usual level make a lasting change, and the declared life event says why without deciding anything.
Life events: a change spotted, a name you choose
Three changes leave a clear trace in your own accounts. Their names do not appear there: higher income may come from a new job, a promotion or going self-employed.
| Change spotted | What is compared | Names you can give when confirming |
|---|---|---|
| Income durably higher or lower | Three complete months against the usual level | New job, promotion, self-employment, business creation, job loss, retirement, other |
| Housing payment | A different payee or a different amount | Move, home purchase, renovation, other |
| Loan | The last instalment is coming up or has just passed | Loan end |
In Avuru, the "My financial profile" screen applies these rules over the period you choose, 36 months by default. Reading your habits is free; the recurring share and lasting changes are part of the Plus plan.
When your financial profile card is active with your consent, these three changes wait under "To confirm": the screen shows the fact, never calls a rise a "promotion", and you name it or dismiss it for good. Withdrawing your consent stops this search.
An event can also carry an estimated effect: an amount, more money available or more spending, once or every month. Upcoming events are marked at their date on the cash flow forecast, and the "With my events" switch draws a scenario curve beside the forecast without replacing it.
A fictional example: a move planned for March with €250 more rent a month takes the scenario curve €250 further from the forecast each month from March. A loan end is already in the forecast, so it is not counted twice. A private event shows there as "Private event".
A spotted change stays a fact until you name it, and the curve with your events stays a scenario.
What these numbers do not say
A transfer from your current account to your savings is not spending, and counting it inflates the total. The guide to internal transfers explains how this works.
A common case: €500 out of the current account on 3 March, €500 into the savings account on the 4th, recorded as two ordinary operations. They add €500 to each column, although nothing has left the household. The pattern: the same amount, opposite directions, two of your accounts, a few days apart.
The payment of a deferred debit card produces the same double count when its purchases are already tracked one by one: €1,200 of purchases and a €1,200 payment make €2,400 of spending.
In Avuru, the "Scope" button of the Habits tab sets the period, the accounts and the categories left out, and a switch goes from spending to income. The spending view points out these pairs, no more than four days apart: you say whether it is a transfer, and nothing leaves the figures without that step.
Amounts in different currencies do not add up without an exchange rate. A cross-border worker paid in Swiss francs into a CHF account, with a current account in euros, has two separate series. A reading that does not convert counts only the accounts in one currency and names the others.
The current month is partial, so it looks lighter than it will end up. With fewer than two complete months, there is nothing to read.
A transfer between your accounts, an unconverted currency or a month still under way distorts the reading more surely than a heavy month.
Frequently asked questions
How do you analyse your spending?
By reading at least twelve months of transactions along three lines: the months that come back heavy every year, the split between the start, middle and end of the month, and the few categories and payees that make up 80% of the total.
What is a seasonal expense?
An expense that comes back in the same month every year: the new school year in September, the holidays in December, an annual tax in October. Under this guide's rule, the month is at least 30% above its year's monthly average, in at least two separate years.
How do I know where my money goes?
By ranking twelve complete months of spending by category and by payee, then adding up the shares until they reach 80%. In the guide's example, seven categories out of fifteen are enough, and uncategorised spending keeps its own line.
Why do we spend more at the start of the month?
Because fixed costs follow the salary, which in Luxembourg is paid by the last day of the month at the latest, according to the Inspection du travail et des mines. Rent, insurance and subscriptions go out in the days that follow. In the example, the 1st to the 10th carries 46% of spending against a baseline of 32.9%.
How do you include a life event in a cash flow forecast?
By giving it an estimated effect, then reading the result as a scenario beside the forecast. A monthly effect is added every month from the event's date, a one-off effect only once.
Key points
- Analysing your spending takes at least twelve months of transactions, read by time of year, time of month and concentration.
- A month is seasonal when it is at least 30% above its year's monthly average, in at least two separate years.
- The 80% threshold is a reading aid, and uncategorised spending stays a separate line within it.
- A transfer between your accounts recorded as an expense and as income counts twice.
- A change is lasting when the last three complete months are all above 125% or all below 75% of the usual level, with a gap of at least 30 units each month.