Bills people forget to budget for (and how to stop them catching you out)
Updated 13 October 2026
Most budgets cover rent, groceries and the phone bill. What breaks them is the bill that turns up once a year and was never in the plan. Here are the common ones, and a simple way to cover them.
The ones that get missed
- Car registration and insurance. Often paid yearly, and often both in the same few months.
- Home or contents insurance. Easy to forget because it renews automatically.
- Car servicing and tyres. Not monthly, but certain to happen.
- Annual subscriptions and memberships. Software, cloud storage, streaming on a yearly plan, gym, sports clubs.
- School costs. Fees, uniforms, books and excursions, mostly at the start of the year.
- Medical and dental. The gap after insurance or rebates, glasses, and the dentist visit that's been put off.
- Pets. Vet visits, vaccinations and registration.
- Birthdays, Christmas and holidays. They come every year, yet they're often paid for with a credit card.
- Home maintenance. A broken appliance, a plumber, gutters, smoke alarm batteries.
The fix: a small amount from every pay
For each one, estimate the yearly cost and divide it by the number of pays you get in a year. Put that amount aside every payday in a separate account. These little pots are often called sinking funds.
Example: car rego and insurance of $1,560 a year, paid fortnightly: $1,560 / 26 = $60 a fortnight. When the bill comes, the money is already there.
An example year
Here's what that looks like for a household with a car and a pet. The amounts are examples only: use your own bills and renewal notices.
| Bill | Per year | Per fortnight | Per month |
|---|---|---|---|
| Car registration | $900 | $34.62 | $75.00 |
| Car insurance | $1,100 | $42.31 | $91.67 |
| Contents insurance | $450 | $17.31 | $37.50 |
| Car service and tyres | $600 | $23.08 | $50.00 |
| Yearly subscriptions | $240 | $9.23 | $20.00 |
| Dentist and glasses | $500 | $19.23 | $41.67 |
| Christmas and birthdays | $1,200 | $46.15 | $100.00 |
| Vet and pet registration | $400 | $15.38 | $33.33 |
| Total | $5,390 | $207.31 | $449.17 |
That's about $207 a fortnight set aside so that $5,390 of yearly bills is already covered when each one arrives. Per fortnight is the yearly amount divided by 26; per month, divided by 12; each rounded to the cent.
Try it: Savings goal calculator: how much to put aside each pay for any cost with a due date.
Start with the next three
You don't need to set up every pot at once. Pick the three big bills due soonest, within the next six months, and start those first. Add the rest over the next few pays.
Common questions
Where should I keep this money?
In a separate account from your everyday spending, so it isn't spent by accident. Some banks let you open several savings accounts or "buckets" and name each one.
What if a bill is bigger than I set aside for?
Pay the difference from your next pay, then raise the amount you set aside for next year. After one year of tracking, your estimates will be close.
How is this different from an emergency fund?
Sinking funds are for costs you know are coming. An emergency fund is for the ones you can't predict, like losing work or a big repair. See the emergency fund calculator.
Keep every pot in one place
The Sinking Funds Tracker gives each cost its own target and due date, works out what to put aside each pay, and shows whether you're on track. Plus a 52-week and 100-envelope challenge.
See the Sinking Funds TrackerGeneral information only, not financial advice.