The price on the windscreen is the beginning, not the end
Used car buying has a cognitive trap built into it: the purchase price feels like the main financial decision, so that's where people focus. In reality, the purchase price is often the smallest number in a full ownership calculation. For a car you keep for three to five years, the total cost of ownership — fuel, insurance, tax, servicing, tyres, and the occasional repair — typically dwarfs what you paid to acquire it.
Understanding this before you buy, rather than after, is what separates people who build wealth through practical car ownership from people who are permanently surprised by their car's running costs.
Start with the real monthly cost, not the asking price
The question to ask before any used car purchase is not "can I afford €6,000?" but "can I afford €X per month, for the next three to four years?" To answer that, you need to calculate:
1. Depreciation
The car will be worth less when you sell it than when you buy it. Divide the expected loss in value by the months you'll own it. A €6,000 car that sells for €3,000 three years later costs you €83/month just in depreciation — before you've put any fuel in it.
2. Insurance
Get an actual quote before you buy, not an estimate. Insurance varies dramatically by engine size, body type, your age, your postcode, and your history. A powerful hatchback might quote twice what a sensible saloon does for the same buyer.
3. Road tax / VED
In the UK, road tax is based on CO2 emissions for cars registered after 2017. Older cars pay a flat rate by engine size. Check the specific car's tax band — it's a real number, not an approximation.
4. Fuel
Divide your estimated annual mileage by the car's real-world MPG or L/100km, then multiply by current fuel prices. Use real-world consumption figures (HonestJohn Real MPG, Spritmonitor, or similar) rather than official WLTP figures, which are consistently optimistic.
5. Servicing
Find out the service interval for the specific car and what a full service actually costs from an independent specialist in your area. An annual service on a Toyota Corolla costs different money than an annual service on a BMW 3 Series. Get a real quote.
6. Tyres
A set of four tyres every 30,000–40,000 km, averaged per month. Premium tyres on 17-inch alloys cost more than budget tyres on 15-inch steels — the car you're looking at will specify which it needs.
Add these up. That's your real monthly cost. Compare it to what you're actually willing to spend on transport, and you have a genuine answer to whether you can afford the car — not whether you can afford to hand over the purchase price.
The emergency fund calculation
This is the step almost everyone skips, and it's the one that causes the most financial pain.
Any used car has a non-zero probability of needing an unexpected repair. The probability and the typical repair cost both depend on the specific engine and its known failure points. For some engines, the 80,000–120,000 km range is where a specific known repair typically occurs. For others, there's no particular danger zone — just the usual random failures of an aging car.
Before you buy, ask yourself: if this car needed a €1,500 repair next month, could I handle it without financial stress? If the answer is no, you have two options: buy a car where €1,500 is an unlikely scenario, or build a repair fund before you buy.
A practical approach: on top of your monthly running cost estimate, set aside €50–100/month into a dedicated car emergency fund. After one year you have €600–1,200 available, which covers most common unexpected repairs (clutch, brake caliper, sensor, auxiliary belt, cooling system component). After two years, you're in reasonable shape for most non-catastrophic repairs.
Without this buffer, a single unexpected repair turns an affordable car into a financial crisis. With it, the same repair is an inconvenience rather than a disaster.
The first week checklist after you buy
This is the part of used car ownership that nobody tells you, and it's the single most valuable thing you can do to avoid expensive surprises in the first year.
Change the oil immediately
Regardless of what the service history says, change the oil in the first week. You don't know how old the oil actually is, how long the car was sitting before you bought it, or whether the interval claimed on the service stamp matches reality. Fresh oil costs €30–70 depending on the car; it's the cheapest insurance you can buy.
Use the manufacturer-specified grade. Not similar — the same. The spec is in the owner's manual and on the Volkswagen / BMW / Toyota / etc. lubricant recommendation page online.
Check the timing belt or chain status
If the car has a timing belt (not a chain), find out:
- What the replacement interval is (typically 80,000–100,000 km or 5 years, whichever comes first)
- When it was last done
- Whether you have a receipt
If you don't have a receipt and you don't know when it was done, budget for a replacement now and treat it as part of the purchase cost. A snapped timing belt on an interference engine is one of the most expensive failures a used car can produce — damaged pistons, bent valves, and potentially a write-off. The replacement itself is not expensive relative to that consequence.
Check the coolant
Look at the colour, the level, and the smell. Coolant that's brown and rusty means it hasn't been changed in a very long time and is probably not protecting the cooling system effectively. Fresh coolant is typically blue, green, or red depending on the type. Budget a coolant flush if it looks old — it's a cheap service that protects expensive components.
Check the brake fluid
Brake fluid absorbs moisture over time, which lowers its boiling point. Old brake fluid in a car driven hard can lead to "spongy" brakes or brake fade under sustained use. If you don't know when it was last changed, change it. It's inexpensive.
Look for leaks
After the car has been parked on your driveway for a day, look underneath. Any fresh wet patches? Oil leaks typically leave brown or black stains under the engine. Coolant leaks leave a sweet-smelling coloured puddle. Power steering fluid (if hydraulic) is typically reddish and appears under the front-centre of the car.
A small leak doesn't necessarily mean a crisis — it means a seal or gasket needs attention. Finding this in week one means you can budget and schedule the repair; finding it after it's caused secondary damage is more expensive.
Check the tyre tread and condition
Legal minimum is 1.6mm in the EU and UK. Practical safety minimum is higher — 3mm is where most tyre specialists recommend considering replacement, particularly in wet conditions. Check all four tyres and the spare. Also check the tyre age (the four-digit code on the sidewall shows the week and year of manufacture) — tyres over six to seven years old should be replaced regardless of tread depth because the rubber degrades with age.
Reset everything and start fresh
Change the pollen filter. It costs very little and you almost certainly haven't thought about it. Check the air filter. Run a diagnostic check with an OBD-II reader (cheap, widely available) to see if there are any stored fault codes — some sellers clear codes before a sale, but stored codes that haven't been cleared tell you a lot about the car's recent history.
The question nobody asks the seller
"What would you fix on this car if you were keeping it?"
Most sellers answer honestly when the sale is done and they don't feel defensive. The answer is often more useful than everything else in the viewing.
Frequently asked questions
Should I always buy the cheapest car I can find?
Not necessarily. A slightly more expensive car from a more reliable engine family, with a documented service history, can cost significantly less over a full ownership period than a cheaper car with unknown history or a problematic engine. Total cost, not purchase price, is the relevant number.
How much should I budget for repairs on a used car per year?
As a rough guide: 1–2% of the car's value per year on a well-maintained example from a reliable engine family. Higher on older cars, on cars from engine families with known issues, or on cars without documented history.
Is an extended warranty worth it on a used car?
It depends on the exclusions. Most extended warranties exclude known issues and pre-existing conditions, which are precisely the things most likely to go wrong on a used car. Read the exclusion list before deciding — a warranty that doesn't cover the engine on a car with a known timing chain issue is not worth the premium.