MOTs, repairs, tyres. Car costs feel random but they’re actually predictable. Here’s how to plan ahead.
Tool: Sinking Fund Planner | Stage: Control
Car costs have a distinctive way of feeling like bad luck when they land. A sudden MOT fail, a set of worn brake pads, a dashboard warning light that turns into an expensive diagnosis. Each individual repair feels like an unfortunate, unpredictable event, but zoomed out across a few years of car ownership, these costs are actually far more predictable than they feel in the moment they arrive.
Why This Happens
Because car repairs don’t happen on a fixed, predictable monthly schedule, they get mentally categorised as unplanned, even though, viewed over a longer timeframe. They’re actually one of the most reliably recurring expense categories most car owners have. It’s rare to own a car for several years without some combination of MOT costs, tyre replacements, routine servicing, and the occasional unexpected repair. The individual timing is unpredictable; the fact that something will need attention. Roughly every year, is not.
This mismatch between “unpredictable timing” and “predictable total cost” is exactly what makes car expenses feel so much more stressful than they need to be. Each individual bill arrives as a surprise, even though the category as a whole is entirely foreseeable.
The Reframe
You don’t need to predict which specific repair is coming, or exactly when, that isn’t possible, and trying to guess is a losing game, what you can predict. With reasonable accuracy, is that some repair or maintenance cost is coming, most years, and roughly how much that category of expense tends to cost you over time. A car sinking fund converts these individually “unlucky” expenses into costs that are, collectively, already budgeted for.
This is a different mindset from treating each repair as its own emergency, instead of scrambling each time something goes wrong, you’re simply drawing from a fund you already built specifically for this purpose.
What To Do
Step 1: Look back at the last two to three years of car costs.
Include everything: MOT fees, any repairs, tyre replacements, routine servicing, and anything else that came up. Bank and card statements will give you a more accurate picture than memory, since these costs tend to be spread out and easy to forget individually.
Step 2: Average this total out to a monthly figure.
Take the total across those two or three years and divide by the number of months. This gives you a realistic monthly cost of car ownership beyond fuel and insurance. Often higher than people expect, but far more manageable when spread out than when it lands as a single unexpected bill.
Step 3: Set that amount aside monthly, into a dedicated car maintenance fund.
Just as with the Christmas sinking fund, keeping this separate and clearly labelled protects it from being absorbed into general spending before it’s needed.
Step 4: Draw from this fund specifically for car-related costs. Nothing else.
The discipline here matters, if the fund gets used for other purposes when it’s not immediately needed for the car, it won’t be there when the next MOT or repair actually arrives.
Step 5: Top it back up after any withdrawal, adjusting your monthly contribution if needed.
If a particular year runs higher than your average (a bigger repair, for example), don’t panic, just note it, and consider whether your monthly contribution needs a modest increase going forward.
Beyond the Obvious
It’s worth noting that this same approach, averaging an irregular cost category over several years and converting it into a monthly figure. Works for more than just cars. Home maintenance, appliance replacement, and other “occasional but inevitable” cost categories all respond well to the same treatment.
Build this alongside your other planned expenses, and the next car bill stops being a crisis and starts being simply the moment you draw on money that’s already there for exactly this purpose.
In practice:
Reviewing three years of car costs, a driver finds an average of £840 per year across MOTs, one set of tyres, and routine servicing. Some years higher, some lower, but averaging to £70 a month. Setting that aside monthly means the next MOT failure, whenever it happens, is already covered.
FAQ
What if I have an older car that might need more unpredictable repairs?
Lean toward the higher end of your historical average, or add a modest buffer, since older vehicles statistically carry more repair risk than newer ones, better to slightly over-save than be caught short.
Does this fund cover fuel and insurance too?
No. This fund is specifically for maintenance and repair costs. Fuel and insurance are typically regular enough to sit in your normal monthly budget rather than a sinking fund.
What if I don’t have two to three years of history to draw from, because the car is new?
Use a reasonable estimate based on the vehicle’s make, age, and typical reliability, and adjust the monthly figure once you have real data after the first year.