My 20 yr old FX has just 147 km on the odo. It actually is 200,147 km. How do we know it is 200,000 and not 300,000? We bought the car at 111,010km. This is a safe bet since the engine was original. (Properly maintained) Suzuki engines fail usually around 150,000 km and need an overhaul. Our did so at 134,655 km. Since we can't reasonably expect a Suzuki engine to fail either at 34,000 km OR 234,000 km, the guess falls to 134,000 km. Comparatively, (properly maintained) Toyota or Honda engines need an overhaul at around 350k km.
Also, good owners maintain a log book with their car. In which they write the daily fuel input, oil changes, brake pad changes, tyre replacement, air filter replacement, seat cover replacement and pretty much everything. Always ask for a log from the previous owner when buying a car. In this way you can also know how many times the odometer has zeroed out.
It's not such a big problem to buy a much run car. I'd prefer a much run car (e.g. 600,000km) over an ill-maintained car any time.
Small cars come with 100,000 km odometer. Cars around and larger than 1300cc come with 1 million km odometer. If you people remember from matric, for every measuring instrucment there are 2 imptt parameters: range and least count.
Car odometers have a least count of 0.1km=100 meters.
Cars (4-wheelers) are designed for 7 years of life.
[In comparison, public buses are designed for 5 years and 2- and 3-wheelers are for 2 years]. Source is a transportation book by James Banks.
By design life we mean the carmaker thinks after this life RMA on the car will be so big that the car-owner would consider scrapping the car altogether and buying a new one.
Otherwise if you properly replace the parts you can run a car for much more time. Like in Pakistan, new cars are comparatively much more expensive, and RMA (labor and parts) much more cheaper, so even the Bedford buses of Ayub Khan's era are running todate.
The range of the meter is decided as probabilistic measure. Small cars (subcompacts etc.) are town cars, meant to be driven in town (especially due to parking issues). It is expected they will complete around 100,000km in their design life.
Big cars are driven on highway. Even in my family, people who drive a lot on highways tend to buy cars w/ big engines. The trend has some reasons. Bigger engines need less effort to drive. They're usually fitted to bigger (heavier) cars which are more spacious (suitable for long drives) and being heavier are more stable in crosswinds.
I know many people who use a town car e.g. coure for daily office commute, and a bigger car or 4x4 for weekends when family accompanies or the trip is long/out-of-city.
That's why it can be resonably expected that cars with bigger engines will put up a lot of miles on them, hence they ship with 1 million km odometers.
1300cc/1600cc is the difference spot in the whole world (though americans and arabs tend to buy even bigger engines like greater than 2800cc for highway cars), but in Asia and Europe, most people either buy a 1000cc or less or town use, and 1600cc-3400cc for highway use (and even bigger for sports use LOLz).