When to trade up

Are regular trade-ups the smart thing to do?

It used to be that regular trade-ups of relatively new cars were the smart way to keep yourself on the road without paying too much in maintenance. But our surveys show cars are lasting way longer than they used to before the big repair bills kick in. So when should you buy a new one? Here's our advice.

Run your car for as long as possible

One of the biggest costs of owning a car is depreciation, and the best way to minimise the effect of this is simple: keep your car longer. Around a third of a new car's value will vanish by the end of the third year, and half by five years. Thereafter, if it's a good car and you look after it, the rate slows down: by 10 years it will still hold around 20 percent of its value.

If you buy a five-year-old car and keep it for five years, you'll lose a lot less than buying new. You might want to run it even longer. The extra costs of replacing worn items in a well-maintained old car should still be a lot less than the depreciation on a new or near-new car. Shop around to keep repair costs down.

Watch for rust

The big warning sign is rust. Once rust takes hold, the car loses value rapidly and it is expensive to repair. If your car has rust, it could be time to sell.

The good news, though, is that rust is not the problem it used to be. Remember all those rusted-out doors and station-wagon tailgates in the 1980s? You don't often see them now, because factory rust-prevention treatments are so much better.

Don't worry about the odometer

Don't worry about the odometer racking up large numbers. Once it clicks over 100,000 kilometres the distance travelled has less effect on the value. We hear of lots of cars that are still reliable at well over 200,000 kilometres.

Should you buy a new car?

Cars depreciate most during their first few years. That makes buying a new car and selling it after a few years a very expensive exercise. But many new cars can be bought at good discounts from the listed price. If you haggle hard to get a good discount and keep the car for at least ten years, you will have the pleasure of buying a new car and you can ensure it is serviced regularly - so it should be reliable. Car safety improvements in recent years also means you will have a safer vehicle.

If buying new is not for you, then find a good car that has got past the worst part of the depreciation. But remember every time a car is sold, dealers take a chunk of profit. You pay that. Look for ...

• Two- to three-year-old cars. They may have the remainder of the factory three-year warranty, and are not too far behind in safety features.
• Slightly older models, including Japanese imports, can be bought with factory-backed warranties under schemes run by the major car importers. The factory checks the cars, fixes any problems and sells them through dealer-approved schemes.
• If your budget won't stretch that far, look for well-maintained models six or more years old, even with over 100,000km on the clock.

Buy a reliable model

Pick from the models we recommend for reliability. For full details, see our Car reliability report.