Underbody rust is almost always the killer or Hyundai’s and Kia’s long before the engines give up. ........ The Mazda is the same, the suspension components are all steel with a very thin layer of black paint and thus they rust badly underneath in wet climates..... Get a good rust free example of either with a full service history then pay £300-£400 to have a professional firm to underseal it for you then look after it and you’ll easily get your 10yrs from it.

10 yrs is a surely a bare minimum. My Ziebarted from new 1980 TR7 has outlasted myriads of the Mazda MX5 which first appeared here in 1990 (a salutory example of what our floundering incompetent British mass market sports car makers should have achieved during the 1980s and beyond). It seems the Asians still don't take corrosion prevention seriously. Mrs F's Peugeot 2008 has not only a well painted undercarriage but also clip-on plastic protectors to protect important underframe areas from erosion. I have just done a wheels-off clean and preventive maintenance in preparation for its MoT at 5yrs old in Oct (I shall do this every 5 yrs). There is of course no rust at all so early in its life, apart from the expected corrosion of the brake discs, easily removed with a hammer and old screwdriver.

As above re rust, rust is not a thing of the past despite what some believe so take some preventative measures.

Most normal cars (preferably avoiding poor designs such as wet cam or oil pump drive belts) will last a long time if driven and serviced sensibly, good servicing is not just changing the oil once a year, change the coolant every few years too, change the gearbox and any other transmission fluids periodically ignoring any sealed for life stickers (not guaranteed for life you notice) that might be seen, change the spark plugs before one corrodes in so tight the plug snaps off and have the brakes serviced by someone competent.

If you did just these things (most if not all are DIY'able) and nothing else you'll still be driving the same car in 20 years time if you want to, seriously cheap motoring, though some engine work is likely on some designs due to carbon building up...ie egr related issues on some Diesels and intake and/or valve issues on some direct injection petrols, but given these usually one off expenses overall cost still cheaper than depreciation on new cars.