Like many things in life, you get what you pay for. With headphones and earphones, a higher cost usually equals higher performance. The bundled, or 'stock', earphones given free with MP3 players -- even expensive models such as the iPod classic or iRiver clix -- are almost always very poor performers. Most music players can produce much higher quality music than the earphones shipped with them are capable of reproducing.

The main benefit you'll get for more costly earphones is better audio quality. Shure's SE series of earphones start from around £70 and offer an incredible improvement in sound quality. Over, say, Apple's white earbuds, the entry level Shure SE110 earphones offer significantly more bass and much greater definition. As sound-isolating earphones, they also help block out external noise such as conversation, keyboard tapping, etc.

At the other end of the scale, Shure's flagship SE530s -- also sound-isolating earphones -- feature three separate micro speaker drivers -- that's more than some hi-fi speaker systems! True, these earphones cost in excess of £300, but the difference in quality is, quite honestly, as different to bundled earphones as high-definition TV is to VHS.

Similarly with headphones, the more expensive cans may be extraordinarily pricey for the same reasons the Shure SE530 are -- precise and powerful audio quality. But there are other reasons. Noise-cancelling headphones can cost around £300 -- Sennheiser's PXC 450s, for example -- but offer a unique technology: they digitally remove ambient noise.

When using a good pair of noise-cancelling headphones on an aeroplane, the noise and rumble from the plane's engines can be almost completely eliminated. This allows you to keep the volume down, thus protecting your ears, and better enjoy your music.

Finally, there are some headphones that are just so carefully engineered and constructed, their cost goes through the roof. Denon's AH-D5000 headphones are constructed from a Japanese wood and produce a sound quality you'd expect from a hi-fi system costing thousands of pounds. Every component in this sort of headphone is carefully selected, meticulously implemented and painstakingly tested for optimum performance. For those that appreciate truly superb audio quality, £500 is an affordable alternative to a £4,000 home audio rig.

The ultimate question is: do you need to spend large sums of money? If you only listen to highly compressed MP3s or FM radio, don't bother spending more than about 30 quid. Heavily compressed music will only ever sound mediocre, and expensive earphones will actually make their inferiority more audible to you. If you use audio formats with bit rates higher than 192kbps -- better yet, lossless -- consider revolutionising your listening experience and parting with some cash. It's a bit of an adventure, but an exciting one.

Good luck!