It's a dilemma every owner of an ageing car faces: do you keep pouring money into repairs, or call it a day and scrap it? The emotional attachment to a faithful vehicle can cloud judgement, but the finances need clear-eyed assessment. Here's how to calculate whether your old car is worth saving in 2026.

The Repair Trap

Old cars rarely fail catastrophically all at once. Instead, they nickel and dime you. A clutch here, some suspension bushes there, a water pump, an alternator. Each repair seems justifiable in isolation – £400 to fix a car worth £2,000 feels reasonable. But those repairs accumulate.

The psychological trap is that each previous repair makes the next one feel more necessary. You've just spent £600 on a timing belt; you can't scrap it now. So when the gearbox starts whining six months later, you feel committed. This sunk cost fallacy keeps uneconomical cars on the road far longer than makes financial sense.

The honest calculation requires adding up everything you've spent over the past two years, then projecting forward. If you've spent £2,500 maintaining a car worth £1,500, you're already underwater. If another £1,000 of work is visible on the horizon, the mathematics are screaming at you.

The 50% Rule

A useful guideline: if a single repair exceeds 50% of the car's current value, it's probably time to stop. A £1,500 engine repair on a car worth £2,500 might seem borderline acceptable, but consider what else might fail soon. Older cars rarely have just one problem.

Some mechanics apply an even stricter test, suggesting that annual maintenance costs shouldn't exceed the car's monthly depreciation plus running costs. For a car worth £2,000 that might depreciate £500 annually, spending more than about £150 monthly on repairs exceeds what you'd pay for something newer and more reliable.

These rules have exceptions. A cherished classic, a rare vehicle, or a car with genuine sentimental value might warrant uneconomic repairs. But for everyday transport, cold financial logic usually points toward replacement sooner than emotions suggest.

Hidden Costs of Old Cars

Beyond repairs, older vehicles carry costs that newer cars avoid. Fuel efficiency has improved dramatically – a 2010 car might use 20-30% more fuel than its 2020 equivalent for the same journey. At current fuel prices, that's hundreds of pounds annually.

Insurance can actually increase for older vehicles as parts become harder to source and repair costs rise. The assumption that old cars are cheap to insure isn't always accurate, particularly for vehicles with known reliability issues or theft vulnerability.

Then there's the reliability factor. Breakdowns don't just cost money in recovery and repairs – they cost time, missed appointments, and stress. The peace of mind from a newer, more reliable vehicle has genuine value that's hard to quantify but very real.

Emission zones add another consideration in 2026. If your older diesel can't enter Birmingham, Bristol, or anywhere in London without daily charges, its utility is compromised regardless of mechanical condition. A car that can't go where you need it has limited value.

When Keeping It Makes Sense

The calculation isn't always weighted toward scrapping. If your car has recently had major work – new clutch, timing belt, brakes – you're starting a fresh reliability cycle. It might make sense to enjoy that investment for a couple of years before reassessing.

Low mileage drivers often find that keeping old cars works financially. If you're only covering 3,000 miles annually, the fuel efficiency penalty is minimal and wear accumulates slowly. The same car driven 15,000 miles yearly faces very different mathematics.

Known cars have known problems. Your current vehicle's quirks are familiar; a replacement brings new uncertainties. Sometimes the devil you know genuinely is preferable, particularly if you've found a trustworthy mechanic who understands your specific car.

Making the Decision

Create a simple spreadsheet. List every repair from the past 24 months with costs. Add fuel costs, insurance, tax, and MOT. Compare this total with what you'd spend on a newer replacement, including any finance costs. The numbers often surprise people in both directions.

Get an honest assessment of what's coming. A good mechanic can identify likely near-future failures – worn suspension components, tired brakes, pending exhaust issues. Adding these probable costs to your calculation gives a more complete picture.

Finally, consider your own situation. If reliability matters – for work commutes, family commitments, or health appointments – the risk of an old car failing becomes a genuine cost even before it happens. If the car is purely optional transport, you can tolerate more uncertainty.

There's no universal right answer, but there is a right answer for your specific circumstances. Run the numbers honestly, consider the hidden costs, and make a decision you can justify financially. Sometimes that means one more repair; sometimes it means a dignified retirement for a faithful old friend.