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Updated: 9 Jun 2022

How to buy the best used car

Buying a used car can not only save you a fortune in depreciation but also put your dream car within reach. We'll help you buy the best used car at the right price.
Daljinder Nagra
Used car dealer

Buying a used car can be an easy way to make big savings over a comparable new car, or to trade up into something that might otherwise be financially out of reach.

Unless you’ve got very specific needs, there’s usually a ready supply of suitable, good-quality used cars. And you can normally drive away as soon as the deal is done. 

Keep reading to find out the pros and cons of buying a used car, what to look for when test driving a used car, and how to save money. We've also highlighted some specific issues to consider if you're buying a used electric car. 

Already know what you're looking for? Head straight to our expert pick of the best cars, including new and used models

Is it worth buying a used car?

Used car lot

Buying a used car is the cheapest way to buy a car in the long run. That's provided you’re diligent, don't pay over the odds for it and choose a reliable model - which we can help you with. Here are a few factors to consider. 

Car deprecation

New cars lose an incredible amount of value when they’re first registered. Typically, a new car could be worth as little as 50% of its original value in just three years – a nightmare for the first owner, but a blessing for used car buyers.

Increased risk of problems

Buying a used car can also be risky, as it can be hard to know how well it’s been looked after and whether it has a hidden history – more on both below. 

You can easily find out which cars are the most dependable as they age, as our unique annual survey of tens of thousands of drivers reveals the most reliable cars

2030 ban on new combustion engines

Buying used is likely to be your only way into a conventional petrol or diesel car after the 2030 ban on new combustion engines. If you’re concerned that an electric car doesn’t suit your needs, buying the correct used car could see you well into the future. 

But make sure you check its emissions levels first. Our independent tests, which we believe better reflect real-world driving when compared with the official tests, will help you pinpoint the high-emission cars to avoid, and the low-emission cars you should consider. 

Are used electric cars a good buy?

Just like a petrol or diesel car, an electric vehicle (EV) will depreciate with age. This can make the earliest models – the likes of the Peugeot iOn, Renault Fluence and first-generation Nissan Leaf – very tempting indeed, particularly when compared with the relatively high list prices of current-generation models.

Consider your needs carefully, as used electric cars can come with unique issues to be aware of. For example, people thinking of buying an EV often have concerns about driving ranges. 

Even when they were new, many early models didn't offer particularly useful driving ranges – something that won't have improved as they age. Some very early cars, such as the Fluence, don't even have rapid charging capability.

Furthermore, if you're looking at a used Renault Zoe or an early Nissan Leaf model, it might be subject to a battery lease agreement, which was originally offered to lower the initial purchase price of the car.

Electric car battery capacity over time

Our latest research* into used electric cars, based on more than a thousand electric car owners, has shown there is a very slight but noticeable decline in usable battery range for older electric cars:

  • 98% battery capacity – electric cars up to three years old
  • 92% battery capacity – electric cars at seven years old

We will continue to monitor the state of battery degradation as we collect more data. While an eight percentage point reduction in usable range over six years might not be a dealbreaker, it’s something to think about if you’re considering a used electric car or want to keep it for the long-term. However, if your car still has a decent range for your needs, it’s not likely to be an issue.

*(Survey: Dec 2019 to Feb 2020; 1,016 electric car owners, with vehicles across class types)

If you’re ready to take the plunge and buy a zero-emissions car, we will help you pick the perfect new or used model for your budget and needs – go to the best electric cars.

Can I test-drive a used car?

Yes, with the seller's permission (and alarm bells should ring if they won't let you take the car for a test drive). 

However, you will need to make sure you're properly insured, as it is a legal requirement to have at least third-party insurance to drive a car (read our guide to getting cheap car insurance). If you have an existing, comprehensive policy, it may cover you to drive other people's cars on a third-party basis. Otherwise, you'll need to take out a standalone, temporary policy to cover the test drive. 

What to look for when buying a used car 

Our 11-point checklist will help you buy a used car with confidence. If possible, avoid making visual inspections in the rain or at night (unless it’s very well lit), as both scenarios make it harder to spot problems. 

1. Check the car's MOT history and servicing records

Provided the car you’re looking at is more three years old, its entire MOT test history can be viewed online. Enter its registration number into the government's MOT check website, and you’ll be presented with details of each test.

Pay attention to advisory notes. These highlight any issue that isn't great enough to cause an MOT failure but which could lead to one if left unchecked. These will become your problem once you’ve transferred ownership. If there are lots of advisories, use the likelihood of impending maintenance work to negotiate a discount. And, if necessary, be prepared to walk away.

You should also inspect the car’s service book for stamps and ask the owner if they’ve kept receipts of maintenance work they’ve claimed to have had done. 

Some newer cars use an online service history, which can make it more difficult to check quickly. Try phoning the dealer that carried out the maintenance; it will have a full record of what work has been carried out.

For more information on negotiating the price of your next car, read our guide on how to get the best price on a car.

2. Inspect the bodywork and chassis

The gaps between all a car’s panels should be even and consistent. Misaligned panels can be a sign the car has previously been in an accident. 

Check that the paint matches on all panels (bright light helps here). It’s often difficult to exactly match the paint on repaired panels that have been resprayed, and a slight difference can suggest a previous owner has had a bump.

Inspect small scratches and dents carefully. A scratch that’s gone through the lacquer and paintwork down to the metal is more likely to develop corrosion.

Find out which products will help you make shallow scratches disappear – we reveal the best car scratch removers.

3. Are the wheels and tyres in good condition? 

Kerbed wheels are an inevitable fact of life, particularly for city drivers. If the damage is superficial and the rims themselves aren’t cracked or bent, then it needn’t be a reason to discount a car.

The condition of the tyres is of more concern. 

  • Tyres need to have a minimum of 1.6mm tread depth to be road legal. Factor this into your offer if they’re close to needing replacing.
  • The tyres should also be free from any cuts or bulges. If you notice either on the tyre’s sidewall, it’s likely the current owner has previously hit a kerb.
  • The tread on each tyre should also be evenly worn. Overinflated tyres tend to wear more in the middle, while uneven wear can indicated that the wheels or suspension are misaligned. This can reduce tyre performance and increase wear and fuel consumption.

Find out more about tyre construction, labelling and how to choose the correct tyres for your car – how to buy car tyres.

4. Check the oil level 

Make sure the car is cold and that it’s parked on level ground. Open the bonnet and check the level of oil in the engine using the dipstick. 

A low oil level could be a sign of poor maintenance. Low engine oil accelerates wear, which could mean more problems as the car ages.

Clean engine oil is a golden yellow colour. If the oil on the dipstick is black rather than brown, it may not have been changed in quite some time.

Check the underside of the engine oil cap for any signs of gunk, which will have a mayonnaise-like appearance. This is a sign that engine coolant is mixing with the oil, pointing towards a failed head gasket – something you should walk away from.

5. Does the engine struggle to start? 

Best Cars

Common signs that there may be a battery problem include:

  • The engine struggles to start.
  • The starter motor doesn't work as hard as usual.
  • The interior or exterior lights dim significantly during ignition.

You should also check the water temperature gauge to ensure the engine is cold when you’ve started it. If the seller has pre-warmed it, ask why, as they may be trying to mask any cold-start problems. Once warm, the engine thermostat gauge should stay at around halfway. Overheating when idling or driving at road speeds could point to a problem. 

If your battery is too flat to turn the engine over at all, it may be possible to jump start the car (if you haven't already been put off the car entirely). But it may also point to a battery that needs replacing entirely. 

6. Check the colour of the exhaust emissions

The exhaust may emit fine white smoke on start up. This is water vapour from the exhaust pipe itself and is totally normal. Once warm, engine exhaust will typically be very fine, so thick smoke is a cause for concern. If you spot one of the below, think twice about proceeding with a purchase. 

  • Black exhaust smoke is a sign that the engine is burning fuel inefficiently. This could be down to a fault in one of several components, such as fuel injectors, filters, sensors, or exhaust gas recirculation valves in diesel cars.
  • Blue smoke suggests the engine is burning oil, which is likely down to a failed seal or gasket allowing oil into the engine’s combustion chamber. 

Our free low-emissions checker reveals CO, NOX and CO2 for hundreds of cars we've tested, so you can make an informed decision on your next purchase.

7. Is the mileage genuine?

The car’s mileage will always be higher than that recorded at its last MOT. If not, it suggests that it has been illegally wound back.

Based on driver feedback in the latest Which? Car Survey, drivers typically drive around 9,000 miles each year, so use that as a rough guide to how heavily the car has been used over its life.

You needn’t necessarily be put off by higher-than-average mileage, (particularly if it allows you to negotiate a larger discount), provided the car has been properly serviced and maintained.

If the mileage seems too good to be true for the car’s age, take a good look at the interior. Heavily worn seats, faded buttons and a shiny steering wheel are all signs that the car is getting on.

8. Inspect the interior and test the electrics

Start with the basics like the lights and the horn, then check the following:

  • The air conditioning blows cold. If the car whiffs of old socks when you’ve got the air-con on, the system could have mould and other bacteria growing inside
  • The heated screens and seats work
  • The electric windows operate smoothly. Check the sunroof too, if the car has one.
  • Check the seats for stains and tears to the upholstery. A smoker's car may also have burn marks around the doors and centre console, or tar stains on the roof lining
  • Close the doors and have a good smell of the interior. A damp smell could suggest water’s leaking in where it shouldn’t
  • Lift the boot floor to check if all the original equipment remains. Most models will come with either a space-saver spare tyre and jack, or a tyre inflation kit. If they’re not there, ask why.

9. Look for cracks in the windows 

Stone chips in the windscreen could develop into a crack and become an MOT failure. Any crack 40mm in size anywhere on the windscreen will need fixing (or the screen itself replacing). This drops to just 10mm if the crack is within the driver's line of sight. 

Be wary if the current owner has applied a particularly dark window tint to either the front windows or windscreen. The law states that any tint on these windows must allow 70% of light through (75% for windscreens). There's no limit on rear windows). It’s an offence to sell or drive a car with prohibitively tinted windows.

10. Take the car for a thorough test drive

Car passenger and seatbelt

While you're driving, think about the following:

  • Is it a bumpy ride? Regardless of how basic the car is, the suspension should absorb most bumps without creating a large jolt in the cabin. If this isn’t the case, or it’s making knocking or crunching noises as you drive, it could point to worn or broken suspension components.
  • Does the clutch slip? If you experience clutch slip or any juddering when moving off or accelerating, this is a sign the clutch is on the way out. Similarly, if the biting point is a long way up the pedal’s travel, the clutch may be due for replacement.
  • Does the car pull in one direction? When driving the car in a straight line on a flat and level road, when it's safe to do so, lift your hands from the wheel slightly. If the car pulls in one direction, the wheel alignment might be off.
  • Do you hear a whining noise when you steer? Turn the steering wheel to full lock at slow speeds. A whining noise may point towards a power-steering pump that’s about to expire, or at least that it’s running low on fluid. The same could be true if the steering is particularly heavy or sluggish.
  • Does the engine make a knocking or tapping noise as you accelerate? This may suggest that the engine is wearing prematurely. If the noise is excessive, it could be a sign of a ‘blowing’ exhaust, which is a result of corrosion causing small holes in the pipe.
  • Do the brakes wobble or pulsate through the steering or pedal? This is a sign one of more of the brake discs could be warped and will need replacing.
  • Is the handbrake stable? Make sure the handbrake holds the car on a hill properly. If the car is fitted with an electronic handbrake, make sure it engages and disengages smoothly.

To save you from buying a car you later regret, you can use the results of our tough tests to choose the best car for your budget - see all of our car reviews

11. Consider getting an inspection check

For a small fee, companies such as HPI will provide a report into a vehicle’s background. This will include details of any outstanding finance and will also tell you if it’s previously been stolen or written off – things that should certainly be ringing alarm bells if they haven’t been declared. 

Further details can also include the number of previous owners and whether it’s been imported. Depending on the service you use, you’ll also get an idea of its value, while reputable vehicle-check providers will also guarantee the accuracy of their data.

Some motoring organisations, such as the RAC, will send out a mechanic to inspect any car you’re thinking of buying. This can cost between £99 and £239, depending on the level of test you require, and the vehicle's age and model. Alternatively, you could also arrange an inspection with an independent garage, with the seller's permission. If the seller isn't amenable to this, question why.

Where to buy a used car

Approved used cars

You don't necessarily need to take a punt on the classifieds. There are several ways to source your used car, including via online car buying services.

There are pros and cons to each, however, so it pays to do your research and work out which one's best for you.

Our guide to where to buy a car explains everything you need to know.

What documents should I get when buying a used car?

V5C registration certificate (logbook)

When buying or selling a used car privately, it is your responsibility to ensure you’ve informed the DVLA of the change in its registered keeper. The traditional way of doing this is for both parties to sign the relevant section of the car’s V5 document (the car’s logbook) and post it to the DVLA. After this, a new V5 document is issued in the new owner’s name. 

To speed up the process, you can use the DVLA online service (available every day from 7am to 7pm) – it can be used by buyers and sellers. Records are instantly updated, and you’ll get a confirmation straight away. 

The DVLA will also automatically cancel the seller's vehicle tax and any direct debits, then refund any full months remaining on the vehicle tax. It is the buyer’s responsibility to ensure the car is re-taxed and that they have appropriate insurance before driving it away.

MOT certificate

Without an MOT certificate, cars cannot be insured and so cannot legally be driven on the road. Always check the MOT certificate has the same vehicle registration and chassis number as the car you’re viewing.


It’s always worth asking the seller to provide a signed receipt that specifies the make, model, engine size, registration, chassis number, the date it was purchased and the amount paid. 

How to save money on a used car

Wherever you choose to buy your next used car, and however you intend to pay for it, there’s always scope to save money.

Get a used-car valuation

Online car-valuation tools give an approximate valuation for any car you’re considering, putting you in a stronger position as a buyer. Most work by letting you enter a registration number and approximate mileage, but you can also often search by make, model and year.

Auto Trader and Parkers are two such providers of online valuation tools, but there are many others. Most valuation tools are free to use, but you'll normally have to provide some details to use them – such as signing up for an account or providing an email address.

Don't be afraid to haggle for a used car

If you decide to buy privately after checking and test driving the car, it's time to negotiate a price. Look for things that could throw up costs in the near future – such as a short MOT or worn tyres – and use these as bargaining points.

Haggling with a dealer may or may not prove successful, but it doesn't hurt to try, especially if you've seen a very similar car for a lower price elsewhere (bear in mind it won't be exactly like for like), or a used-car valuation suggests the dealer's asking price is on the high side.   

We've got expert tips on haggling, including our tried-and-tested script. So make sure you read our guide on how to get the best price on a car.

Be flexible on the model of car

Models that are typically in demand, such as the Volkswagen Golf and BMW 3 Series, will tend to resist depreciation better. This means they will command a slightly higher premium than similar models on the used market.

So, if you're open-minded, you could save money on your next used car. Choosing an unfashionable body type (an estate over an SUV, for instance), a less well-known manufacturer or a less popular engine type could all help you bag a bargain.

One thing to be wary of is the lure of the cheap luxury car. They're expensive to keep on the road, servicing and maintenance costs won't get any cheaper over time, and we've found they can be more likely to give you problems as they age. And even used models might continue to depreciate steeply after purchase.

To find out which brands are the most, and least, reliable, read our guide to the most reliable car brands.

How to save money on car insurance

As a minimum, you'll need third-party insurance cover to use your car on public roads. However, we recommend going for fully comprehensive cover - this means your car is completely protected.

Insurance costs can vary wildly, but there are plenty of ways to reduce your premiums and it always pays to shop around.

Read our guide to comparing cheap car insurance to find out more.

Ready to get out there and find a used car to buy? Don't make your final decision until you've checked our car reviews