My daughter turned 17 this month. Too young to drink alcohol legally but not too young to get her learner's licence, slap an L on the back of my car and head out to do (supervised) battle on the roads. I don't use that word lightly. It has indeed become a battlefield out there for all of us, let alone learner drivers: too many cars for the urban road systems to cope with; drivers blatantly flaunting the rules of the road and/or lacking basic driving skills; drivers with one hand clasping phone to ear, or texting with the tell-tale head bob and car weave; tyre-popping potholes and load-shedding turning robots dark and intersections into accident-waiting-to-happen zones.But for the parents of young drivers, or those who've finally reached the point at which they can swap taxis for their own set of wheels, buying a car is where the battle begins.So here are the most important things to consider when buying a car.NEW CARSCheck the re-sale value, fuel consumption and cost of the parts (Google "Kinsey Report") to get a real idea of the car's cost.The on-the-road fee is an unjustified layer of profit. Negotiate.Beware the term "demo". In many cases it's simply a used car with significant mileage.USED CARSChoose a reputable, franchised or well-established dealership with a reputation to uphold.Ask to see the service book and spare key. If they can't provide either, or make promises to get them to you "next week", walk away from the deal.Take the car's VIN number to one of the brand's authorised dealerships and ask them to check its history.If buying a warranty, check the terms and conditions carefully and insist on being given policy documents.If you ask about accident damage and are told "just a fender bender", ask what steps the dealership has taken to check out the accident history. Also ask for the previous owner's contact details so you can do your own checks. If you don't get proper answers, move on.PRIVATE SALESKnow that the sale is voertstoets - the Consumer Protection Act does not cover private sales at all.Get a Dekra-AA technical report on the car before committing.AUCTIONSMany cars on auction have no service book or manual, so check.If a car you're interested in has no service book, get its details and approach a dealership authorised to service that brand and ask it to check out the car's service history on its records system.In the case of a bank repossession, ask to see the vehicle's logbook. If it has indeed been repossessed by the bank, the bank will be listed on the document as both the titleholder and the owner.Employees of auction houses do not drive the cars so can't vouch for their condition."It boggles the mind when I see how little time people spend on researching their purchase of a car that is, without doubt, the second-most expensive article any ordinary person will ever make," said motor industry ombudsman Johan van Vreden.Too true. So, before you buy, interrogate.CONTACT WENDY:consumer@knowler.co.zaTwitter: @wendyknowler..