Can I replace just the bulb of my car's xenon headlamp if it blows? The regular halogen bulbs are easy to replace and are not costly.

The good old halogen bulbs are still fitted as original equipment on many cars these days. They are easy to replace and even the most high-quality ones cost no more than $60 a pair.

These bulbs last about five years, assuming 25 per cent of the average motorist's driving is done at night.

Xenon bulbs consume less energy yet produce two to three times the levels of illumination of halogen bulbs. They are fundamentally different from filament bulbs like halogen.

Although the primary power supply is from the car's 12-volt electrics, a dedicated high-voltage module feeds 10,000 to 20,000 volts into the bulb's electrodes to create a gas plasma inside.

Xenon bulbs can be removed, but the process is not as straightforward as removing a halogen bulb. Tools will be needed and access points can be tight and awkward. Sometimes, it is also necessary to "reboot" the headlamp-ECU (electronic control unit) to re-establish its light-beam alignment.

Authorised dealer workshops typically charge $500 to $700 to replace a xenon bulb. After-market items are of course cheaper, but unless they are of a reputable brand, you have no assurance of longevity.

Fortunately, xenon bulbs typically have a lifespan of about 2,000 hours, which roughly works out to more than 10 years for the average motorist.