How to budget for the expenses that only happen once a year
The insurance premium, the school fees, the car service, the trip home. A monthly budget that ignores them is slightly wrong every month and catastrophically wrong in one, and the fix is arithmetic rather than willpower.
A household budget that covers rent, food, energy and transport can look entirely sound for four months and then fall over in the fifth for reasons that were completely predictable in advance. The insurance renews. The car needs its service and two tyres. The school asks for the trip money. The boiler, which has been making that noise since February, stops. Suddenly a month that was budgeted at a comfortable figure comes in at nearly double, and the household concludes that something went wrong.
Nothing went wrong. The budget was simply describing a household that does not exist — one with no annual costs. Every month it was slightly too optimistic, and the accumulated optimism arrived all at once with a due date on it.
Why a monthly budget without them is wrong every single month
This is the part worth internalising, because it changes how the problem feels. If your household spends twenty-four hundred a year on things that do not happen monthly, then your true cost of living is two hundred a month higher than your monthly budget says. Not occasionally. Always. Every month in which none of those bills lands, you are running a surplus that is not a surplus — it is money that already belongs to a bill that has not arrived yet, and if you spend it as though it were spare, you are not overspending in the month the bill lands. You overspent in the eleven months before it.
That reframing moves the failure from where it feels like it happened to where it actually happened. The month with the insurance in it is not the problem month; it is the month the problem became visible.
It also explains why these costs feel like emergencies when almost none of them are. A car service is on a schedule, an insurance policy has a renewal date printed on it, and school terms are arranged a year ahead. Calling them emergencies has a cost: it sends them to the emergency fund, which then never has anything in it for actual emergencies.
Finding them: the one job that needs a year of history
You cannot list these from memory. Everyone tries, everyone produces six of them, and everyone is missing four. The reliable method is to look back over a full year of records — bank statements if that is what you have, your ledger if you have been keeping one — and pull out every payment that did not occur monthly.
This is the single thing a year of history does that a month of history cannot do at all, and it is the strongest practical argument for keeping records over a long period even when nothing much seems to be happening with them. A month tells you about food. A year tells you about the structure of your obligations.
The list for a typical household is longer than expected. Working through a year usually surfaces:
- Insurance of every kind — home, car, health, life, travel, the pet — some of which renews annually and quietly increases each time.
- Vehicle costs: servicing, tyres, the annual test, road tax, the repair that is not annual but happens roughly every other year.
- Education: fees, uniforms, materials, trips, the club that invoices per term rather than per month.
- Travel that is not a holiday — the trip home for a family occasion, which is not optional and is not in anyone’s budget.
- Gifts and celebrations, which are individually small, collectively substantial and almost never planned for as a total.
- Annual subscriptions taken out for the discount, which is exactly why they are invisible eleven months out of twelve.
Appliance replacement is where honest budgets and comfortable ones diverge, because it is not an event but a rate: six thousand of appliances lasting eight years is seven hundred and fifty a year of replacement cost whether or not anything broke. Most households never book it, which is why every failure feels like an ambush.
The sinking fund
The mechanism is old, unglamorous and effective. List the irregular items for the coming year, estimate each from last year’s figure plus a margin because these costs tend to rise, total them, divide by twelve. That figure is now a monthly obligation sitting in your budget alongside rent, and it is not available to spend.
This converts an unpredictable series of shocks into a boring fixed cost. It does not reduce what you spend by a single unit of currency; it changes when you feel it, which turns out to be most of the difficulty. A household that finds four hundred alarming in one month often finds thirty-three a month unremarkable, and it is the same money.
Where to hold it
Somewhere separate enough that you do not spend it by accident and accessible enough that you do not have to break something to get it. A second savings account is the usual answer and it is a good one, precisely because the small friction of moving money back is enough to stop casual raids without preventing legitimate ones.
Where not to put it: anywhere whose value can fall, and anywhere you cannot get at within a few days. This is money with known due dates in the near future, which makes it the clearest possible case for boring storage. That is a statement about matching the horizon of the money to the horizon of the obligation, not investment advice — what to do with money beyond that is outside what any budgeting guide should be telling you.
The sinking fund and the emergency fund should not be the same pot. Merging them means the emergency fund is never funded, because the car service keeps eating it.
The first year is ugly and there is no way around it
The obvious objection to all of this is that it assumes twelve months of runway before the first bill, and nobody has that. The insurance renews in March whether or not you started setting money aside in January.
So the honest first-year plan is triage rather than a clean system.
- List the irregular costs with their actual dates, in date order rather than by size.
- Work out how many months you have until each one. The March bill has two months of funding available; the November one has ten.
- Fund by deadline, not by amount. The nearest bill gets whatever you can spare first, even if it is not the largest.
- Part-fund without embarrassment. Having sixty percent of the car service saved is a materially better position than having none, and it is not a failure of the method.
- Accept that some of year one gets absorbed some other way — a lean month, a smaller holiday, or credit you then repay. Year two is the one where this works, and it does work in year two.
- At the end of year one, redo the list with real figures. It will be more accurate and usually larger.
Do you log the set-aside as spending or as a transfer?
A genuine question with no universal answer, and the choice determines what your monthly total means.
Book it as an expense and your monthly figure becomes your true cost of living — a number you can compare against income and treat as the real answer to "what does this household cost". The downside is that your category totals now contain money that has not bought anything yet, so a month can look expensive when nothing happened.
Book it as a transfer, with the spending recorded only when the bill is actually paid, and your categories stay clean and your monthly totals stay lumpy — you are back to a quiet month and a terrible month, except now you have the money. Some households do both: a transfer for the movement, and a separate annual review of what the irregular costs came to.
Pick based on which question you ask more often. If you are trying to work out what you can afford long term, book it as an expense. If you are trying to see what you actually bought this month, book it as a transfer.
In Fambook terms, the options are worth being plain about. A rule that generates an entry automatically every month is a repeating entry, which is part of the subscription. A monthly limit per category is free. And the version that costs nothing at all is the one most households should start with anyway: a category for the set-aside, one entry a month made by hand, and a note saying what it is for. It takes about ten seconds a month, and the arithmetic — which is the part that actually solves the problem — is identical.
The temptation with irregular costs is to look for a feature that handles them. There is no such feature. There is a list, a total, a division by twelve, and a decision to treat the result as a bill rather than a preference.
Frequently asked questions
What counts as an irregular expense?
Anything you pay less often than monthly but reliably enough to be foreseeable: annual insurance, vehicle servicing and tax, school fees and trips, professional subscriptions, the yearly trip home, gifts, and appliance replacement. The last one is the most commonly missed, because it does not arrive with an invoice until something breaks.
How much should I set aside each month?
List the irregular items for the next twelve months, estimate each from last year plus a margin because these costs tend to rise, total them and divide by twelve. That figure is a monthly obligation rather than a preference, and it belongs in the budget next to rent rather than in the space left over.
Where should I keep the money?
Somewhere separate enough that you will not spend it without noticing and accessible enough that you can reach it in a few days. A second savings account does both. Money with a known due date within the year should not be anywhere its value can fall.
What if I have not got a year of history to look at?
Use whatever you have and expect to miss items. Bank statements will cover most of the recurring payments even if your ledger does not go back far enough, and you can add what you find as it happens through the first year. This is the one budgeting job that genuinely gets better with a long record, which is a reason to keep one now rather than a reason to give up.
Should the set-aside show up as spending in my monthly total?
It depends on what you want the total to mean. As an expense, your monthly figure becomes your true cost of living but your categories contain money that has not bought anything yet. As a transfer, your categories stay accurate and your months stay lumpy. Choose according to which question you ask more often, and stay consistent.
Can Fambook do this automatically?
A rule that generates the entry each month is a repeating entry, which is a subscription feature. Everything else you need is free: a category for the set-aside, budgets, and a year of history to find the items in the first place. Making one manual entry a month achieves the same result, and the arithmetic is where the value is.
Try it for one month
Fambook gives a household one shared ledger: anyone can add an entry in seconds, every entry says who spent it, and the month adds up in one place instead of two. Records with no signal and syncs afterwards. Recording, categories, budgets, statistics, CSV import and export, sync and sharing for two people are free — the subscription only buys you less typing.