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I am in the process of buying a used car and I'm having some difficulty estimating the longevity of vehicles I encounter.

One can speak of car longevity in different ways, but for this question let's consider only longevity in relation to mileage, and assume no major part replacement (ie. disregard cases like engine replaced after 50k miles, resulting 80k car with a 30k engine). I expect that miles-to-failure for a given model of car will have some sort of distribution with a pronounced mean (the naive expectation would be Poisson distribution). I am interested most in the median of this distribution.

Certainly manufacturers must have extensive data on such distributions for all of their cars. I imagine service professionals will be well acquainted with it as well. However I have not been able to find any standardized (ie. so that I can compare different car models), comprehensive (ie. has most cars, most models, most years, considers various customization options if they make a difference) set of data.

Mechanics I spoke to have only been able to give very vague answers ("I've seen that car do 200-300k miles sometimes"). Searching on the internet I've found only similarly unhelpful, anecdotal, imprecise answers. Marketing material from manufacturers doesn't seem to discuss this very much, and it's hard to find marketing material for older models anyhow.

Is there a resource I can go to for such longevity statistics for cars by make, year of manufacture, model and trim? Ideally I would like to miles-to-failure by kind of failure (ie. which component breaks) but it would be sufficient if I just knew miles-to-failure until first major (ie. costly to repair) mechanical problem.

My goal is not to estimate how long a given car will last me, but to make an apples to apples comparison between 2 given cars to determine which one is farther along its typical lifespan.

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This page from 'Honest John' shows the MOT pass rates (UK roadworthyness test) for various cars, broken down by make and model, and then by category (i.e. what failed), although they seem to be a couple of years old - 2013 being the most recent results. That's taken from the government database, so is likely to be the most comprehensive, at least from a UK perspective.

A lot of it depends on how well a car has been maintained, and how it's been used, more than what make it is.

  • In the UK cars don't have to be MOTed for the 1st 3 years so they don't get an MOT until their 3rd birthday, from then on it's yearly. That's why you don't get results from the last couple of years. – squigbobble Feb 1 '16 at 10:19
  • That is very useful, thanks! With regards to the maintenance, you're right, but since I doubt I will find any statistics that factor in maintenance and use, I am left with no choice but to assume that driver fastidiousness is about the same wrt car model. My aim is to compare longevities of different car lines in a general sense, not to look at an individual used car and try to guess how long it will last. – Superbest Feb 1 '16 at 18:48
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The ADAC (German roadside assistance) creates an annual report of how reliable cars are, i.e. how many times they have to do roadside repairs relative to how many cars of this type are registered in Germany. This is about the best information you can expect to find. The MOT info mentioned by Nick C should also be good.

Life expectancy of parts is dominated by driving style (incl. whether you do long/short trips, amount of load carried) and location (mountainous/flat)/weather. So any average numbers will have huge deviations.

After about 3 years, many cars fall off the manufacturer's radar. They're out of warranty, so many owners will switch to cheaper independent garages which won't give information to the manufacturer. I don't think manufacturers keep enough old cars themselves to get any sort of reliable data.

There is one more data point you could use: the sales price of second-hand cars. Once the price drops below $2000 or so, you've come within the bracket where the next garage bill will mean an economic writeoff. That's not to say the car's at the end of its life at that point. You can keep the car running for years to come for an annual budget in the region of $2000. Basically you trade the absence of writeoff cost (the car's value will remain pretty constant for years) for an increase in maintenance cost.

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There is also the Finnish page for mandatory inspections by A-katsastus here: https://www.a-katsastus.fi/vikatilasto

Click the link "Vikatilasto 2015" (will change to 2016 quite soon, and then to 2017, and so on...). "Matkamittarilukema/1000" means average odometer reading in kilometers divided by 1000. The percentage is the percentage of failed cars, and the first row is the average for all cars of this age.

Overall, most similar statistics show that for old cars, Toyota is the leader, having the smallest number of faults, although some cars that are driven less and maintained more carefully like Porsche can have good failure percentages as well.

Occasionally, people say that the quality of Toyota has recently went down because Toyota does not show a leadership in the most recent cars. Usually, such statements can be falsified by waiting for 10 years and showing that indeed, the cars that used to be new but are after 10 years old have Toyota as the leader. Unfortunately, any such statement not older than 10 years cannot be easily falsified now.

Also, consider this: not all faults are shown in these statistics. They contain only those faults that are part of the inspection. So, for example, if the locks occasionally fail to work in cold weather or if the synchronizers of the gearbox are worn, the faults won't be shown. My 2011 Toyota Yaris that had both of these faults had never failed an inspection. These problems and the lack of all wheel drive led me to change to 2016 Toyota RAV4 hybrid that has had none of these problems.

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