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What Is Good Mileage for a Used Car?

Buying a used car can understandably be an anxiety-inducing experience. When you buy a used car from a garage, you typically get some kind of warranty, but these warranties will often be limited to critical problems and labour, leaving plenty of room for expensive repair bills if your used car choice wasn’t the best.

And, of course, buying a used car from a private seller usually comes with no warranties or guarantees. While there will always be risks involved with buying a used car, there are a number of things to look out for that can reduce the possibility of buying something with catastrophic problems hiding away, and one of the most obvious is the mileage. The number of miles a vehicle has done is a clear indicator of how much wear and tear it has suffered and makes a solid starting point in determining whether the vehicle is good value for money or even worth buying at all.

Of course, mileage should never be the only factor considered, and we'll get into that in more detail below. But for the vast majority of used vehicles, mileage is probably the single most accurate indicator of a vehicle's condition. You may think that using your eyes would be more effective, but a car's exterior could be immaculate, yet it may be only a few thousand miles from needing a new engine! Likewise, a vehicle could be covered in scratches and dents but still be one of the most well-maintained vehicles on the road. As with many things in life, looks can be deceiving. Let's dig deeper into this topic.

What does mileage mean?

For the younger road users, "mileage" might be a bit of a confusing term since Ireland officially moved away from miles over a decade ago. Mileage refers to the distance the car has travelled since it first rolled off the factory line. That distance is officially measured in kilometres for Irish vehicles, but the term "mileage" is often still used. Indeed, all cars sold in Ireland since 2005 have been required to have speedometers that only display kilometres per hour. For this article, we'll be using kilometres as our unit of choice, as it is intended for Irish readers.

Mileage is generally a better indicator of the car's condition than its age because while time does take a toll on a vehicle, it is the wear and tear of use that causes the most damage. Mileage refers to the number of miles the vehicle has travelled and does not factor in the length of time the engine has been running. In the vast majority of cases, this will be an insignificant distinction since the amount of time an average vehicle spends idling is only a small portion of the time it spends driving.

Of course, you should never only consider one aspect of a vehicle when buying used. Even though the mileage is possibly the most useful metric, it is not foolproof — a car with low mileage can still have problems. It's important to understand that you need to consider the whole picture, including your own circumstances. For example, if you absolutely cannot get by without transportation and are working with a tight budget, any road-legal car is better than none. Alternatively, if you currently have a vehicle and want to upgrade, you can afford to be patient and look for the right vehicle. Now, with mileage explained and this disclaimer out of the way, let's discuss how to determine good mileage from bad.

Why is mileage a good indicator of condition?

Before you can understand what a good mileage looks like, you need to understand why mileage is significant. Vehicles are subject to considerable wear and tear when they are used regularly. Much of this is mitigated by having components designed to be replaced regularly, such as tyres, filters, bushes, and more. Unfortunately, many parts of a vehicle cannot be readily serviceable in this manner, but they are subject to wear and tear all the same. These include the components inside the engine itself.

With proper maintenance, an engine can live a long and healthy life before needing any kind of serious work, such as a rebuild or a replacement. But even with proper maintenance, an engine will eventually need some serious attention. It's a matter of "when" rather than "if". The same goes for the other parts in a vehicle, such as the transmission, brake lines, and even the motors powering electric windows or mirrors. The more use a car has seen, the more likely it will need some serious — and likely expensive — work down the road. Mileage is your best indicator of how much use a vehicle has seen.

What is good mileage for used cars?

An average road user in Ireland will travel roughly 17,000 km per year in their car, so the first thing to consider is the age of the car. Divide a car's mileage by its age, and that figure should be around 17,000 km — give or take one or two thousand. For example, a three-year-old car should have around 51,000 km on the clock. This car has been driven much less than average if it is significantly under that. Significantly over and…you get the idea. Of course, there are other factors, but as a general rule, if a used car's mileage is under this amount, it's a good thing. It is a good rule to go by if you are only looking to get the best second-hand car you can, but that's unlikely to be the case. Money is going to be important — after all, if money weren't a concern, you probably wouldn't be buying a used car in the first place.

With that in mind, the next thing to consider is the price. Cars with higher mileage should be cheaper, so you shouldn't automatically write off higher-mileage used cars if you are limited on funds. You'll still need to consider a few things depending on what the actual mileage is, but the fact that it's higher should be an automatic deal-breaker.

The mileage itself is important, however. Every engine is different, but a general rule of thumb for how long an engine should last (assuming it is looked after and properly serviced) is about 300,000 km. If a used car is creeping up on that figure, it should definitely be treated with extreme caution. But, here's where it's important to consider all aspects: a car with 150,000 km on the clock should be quite a bit cheaper than a car of the same model and year that only has 60,000 km. If you don't expect to be doing many, you should still get plenty of use from the first car before it develops any serious problems. On the other hand, if you are going to be driving a lot, the money saved by buying the 150,000 km car could soon be wiped out by the cost of repairing your engine.

Another important factor is the service history of the vehicle. Not every car owner cares for their vehicle as they should, and it makes a difference. A vehicle with low mileage and no service history should be treated with caution, as it may very well be a worse bet than the same model with higher mileage that's been looked after well. That is why you should never consider just one factor when deciding whether a used car is a good deal or not.

Things to consider besides good mileage

As we've mentioned, the above advice is good for most situations, but there will always be exceptions. Here are a couple of other things to look out for:

Rolled-back speedometers

The days of literally winding back speedometers may be behind us, but the practice of rolling back the clock to make it appear as though the vehicle has done fewer miles than it truly has is still alive and well. Your best defence against this is to check the previous mileages recorded during past NCTs to see if the pattern makes sense with the current mileage. While this does happen, it's also worth noting that it's not very common.

Engine replacements

In some cases, when an engine breaks down, it is cheaper to replace it than rebuild it. This situation is worth considering because the engine is the most significant component in the vehicle when considering mileage, and the mileage of the donor vehicle could have been significantly less — or more — than the car it is in now. Documentation on the mileage of the donor vehicle and the date of the engine replacement should be provided by the seller.


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