Some of today's highly specified new models seem to suffer from equipment overkill. Car manufacturers claim that consumers demand all these extra features. In economic terms, lengthy lists of extra-cost items boost carmakers' profits; they also add value for buyers by creating opportunities to personalise mass-produced cars to reflect individuals' requirements.

Equipment choices are now so complex that new car spec and option lists can make your head spin. You may appreciate air conditioning, luxuriate in leather seats, and understand that ABS and airbags are important for your safety... but what are EBD, sat nav, xenons and 17-inch stars?

When you're planning to buy a new car, the right specification is obviously essential to your enjoyment of the vehicle. But while an electronic games console, white leather upholstery, 'blackout' privacy glass and the biggest alloy wheels available may make sense to a certain type of new car buyer, they won't impress many used car buyers. So look ahead when specifying extras - what value and appeal will they add when you come to resell?

If an item has a broad benefit applying to all owners - safety (e.g. side airbags), comfort (e.g. climate controlled air conditioning), or convenience (a parking sensor) - it's probably worth adding to your specification requirements. But think very carefully about 'vanity' choices like over-the-top interior trim or fleetingly fashionable colour schemes.

With an eye to likely future used car demand, we've compiled a table on the next page showing what equipment on new cars is generally viewed as essential or desirable in various sectors of the car market: