The A to Z of car hire

The key facts you need on vehicle rental before you pick up the keys.

Alicante airport – one of the top destinations for car rental, and a location seeing another squeeze on capacity this summer, along with popular Iberian airports such as Malaga, Palma and Faro. Hertz is quoting £272 for a compact car for a week picking up tomorrow, with unlimited kilometres (the usual practice these days). Although many people are accustomed to a figure around half of that, rates are high in summer: given the short season, it is not worth the rental companies deploying too many cars to these locations. And on the subject of picking up a car when you land – the fees levied by airport operators can make it worthwhile hopping aboard a bus, train or cab to the city centre and renting there.

Brokers – intermediaries who may, thanks to their extra buying power, be able to get you a better deal than going direct. That week in Alicante is showing at £175 on Holidayautos.co.uk.

Counterpart – that green paper slip you got with your driving licence but have now mislaid. Technically the rental company can demand it, to make sure you have not been banned, but in practice this seems to happen only in Northern Ireland. If you don't produce the counterpart, they may offer to call the DVLA and charge you £10-£12 for the privilege.

Dents – the reason digital cameras were invented was to allow you to photograph the car before you drive it away to prove that the bodywork was damaged prior to your rental. Otherwise, you could pay out to get them straightened out.

Empty – the state of your wallet if you return the car without fuel when the company is expecting it to be full to the brim. A punitive price for fuel is usually applied. Some firms offer "out empty, back empty", which is a swizz because none of us can hope to judge it exactly right. The option to buy the tank of fuel is usually worthwhile only if you are pressed for time; in some countries, such as Canada, it is the normal policy. Oh, and when you arrive at a petrol station and don't know which side the fuel cap is, the little picture of the petrol pump should tell you – in my experience it is placed on the dial to the side on which the cap is located.

Former car-rental vehicles are easily available for purchase, thanks to the concept of "buyback" – the bedrock of the rental business. Car hire firms agree with the manufacturers to buy the vehicles back after a certain number of miles, perhaps 15,000, or months (usually six or seven). One careful owner? Possibly not. F is also for Ford, which owned the world's biggest car-rental firm, Hertz, for a decade until 2005. Other makes are now available (indeed, they always were).

Green – a few companies are starting to offer the Toyota Prius and the like, but a brave attempt by a car-rental firm in the 1990s to offer folding bikes with vehicles proved a cul-de-sac. Avis helps reduce your footprint with a "Top 10 Eco Driving Tips" advice sheet. Number 8: keep the windows open and the air-con off.

Hitch-hikers – while hitching a lift is the most environmentally considerate form of transport, Holiday Autos warns renters to "never pick up hitch-hikers".

Insurance – where many elements of the car-rental industry make lots of money, selling "supplemental liability insurance", "personal effects coverage", or "personal accident insurance". Book and pay for everything in advance, and for the one element to which the usual rental is exposed – collision damage – you can buy a fixed-rate annual waiver in advance. Just search online.

Jalopy: the Rent-A-Wreck firm has been offering used cars for hire in the US since 1968, and has expanded into Denmark, Norway and Sweden.

Keys – of course they come in all shapes and sizes, but the crucial thing is: what you do with them at the end of the rental. Often the office will be unstaffed, and you may just drop them into a box. But renting from Thrifty in New Zealand, for example, you may be instructed to return them to an Air New Zealand desk, or even – in the case of the central Auckland branch – "the BP petrol station at the bottom of Khyber Pass Road".

London congestion charge – usually paid for vehicles picked up within the capital's congestion zone.

Multi-purpose vehicles (MPVs) of remarkable size can be rented in the US; Enterprise will hire you a 15-seater from Los Angeles for less than $1,400 for a week, about 150 per cent more than its smallest car.

'Non-returned" (or nicked) rental cars are a nightmare for the industry, with organised crime using cloned credit cards to procure vehicles.

One-way rentals – a breeze if you stay within a single US state (usually California or Florida), or on many journeys within a single European country, but very expensive if you start crossing borders, as many affected by the volcanic ash cloud this year discovered.

Premium location surcharge – usually for big cities. In Ireland, Dollar has a €28 fee for picking up in Dublin or Cork rather than from smaller towns.

Queuing is not necessary if you enrol for one of the multinationals' elite clubs, such as the Hertz Number 1 Club Gold (requiring three annual rentals in the US; make it 30 and you can use the "Designated President's Circle Parking Stalls").

Return – make sure you do so within the time allowed, or you could end up with a host of extra charges. You are allowed a bit of slack, but don't push it: Alamo has a 29-minute "grace period" within the EU, or "thereafter a further full day's rental will be charged".

Stansted – one of several UK airports with special deals for people who want a one-way rental to or from their home. Avis has offered these for as little as £20, much cheaper than airport parking or taxi fares.

Thirty – the average number of miles, in my experience, that you can drive before the fuel needle begins to drop from full. Therefore, the radius from the drop-off point from which you can start looking for a filling station at which to refuel.

Upgrade – never, ever voluntarily upgrade. You will end up paying a small fortune. Steadfastly and politely decline all offers, even when the rental clerk looks amazed and says "you're not thinking of driving all the way to Miami in that?" In my experience, if you book the smallest, cheapest car you will often get a free upgrade anyway.

Volvo XC90 – part of the Hertz prestige collection, which also includes BMWs and Mercedes. This 4x4 SUV will cost £1,259 for a week if you pick it up at Nice airport tomorrow.

Wine – even a sip will send you over the limit, and invalidate your insurance in Pakistan, Cuba, Indonesia, Romania, Jordan and Nigeria, according to Rhinocarhire.com, which produces a comprehensive guide.

XS – industry shorthand for insurance excess, ie the amount you have to pay towards damage or loss. Typically £500, €500 or $750, unless you pay insurance to reduce it.

Young people – anyone under 25 may be refused, or have to pay a premium or accept a higher damage excess.

Zimbabwe – yes, you can even rent a car in this beautiful but troubled nation. Europcar has a Kia Picanto for £292 for a week starting tomorrow, barely more than the rate in Alicante.

All figures quoted are for a week's hire starting tomorrow (8 August)