If you're thinking about buying an MP3 player, here's what to consider:

Flash or hard disk

Players with a flash memory have no moving parts so they tend to handle the knocks better than hard disk players (handy for joggers). Everything required to store and play the digital music files is included on the chip.

Hard-disk players (example pictured right) store the files on a hard drive like the one in a computer. This makes them larger and heavier than flash players, but means they can store far more music.

Size

File formats used by digital music players are comparatively tiny. 4GB players will store about 1000 songs at top quality. Some of the hard-disk models will hold several thousand tracks as well as video files.

Screen

Screen size can be important. The small display screens on flash players (as pictured right) can make it harder to sort through your catalogue of music to find your favourite track, or to view video files. But a bigger screen also means a heftier player and a greater load on the battery.

Recharging

Batteries may be recharged from the USB port in your computer, from a power point (using an AC adapter), or both. If using a USB port, the player may plug directly into the computer or require a USB cable.

Compatibility

If you use a Mac or an older PC, it's important to check that the player is compatible with your computer.

Video

Most new players can display pictures and play video. If these are features you're likely to use, make sure you get a player with:

• long battery life - watching video uses much more battery power than listening to music
• a decent-sized screen
• plenty of storage - a two-hour movie will take up about 1.5GB.

Memory upgrade

MP3 players with upgradeable memory are becoming less common. Some players are not supplied with any inbuilt memory so you have to buy your own memory card. The advantage is you can choose any size memory you want, and upgrade at any time. Memory cards vary in price depending on the type. For example, a 2GB SD card can cost as little as $40-50, whereas a 2GB micro SD card will cost around $60.

File formats and download sites

Although the players are called MP3, most downloadable songs aren't actually in MP3 format. There are several different formats and some players will play some but not others. For example, download sites Digirama and Rip It sell WMA files which will play on Windows computers and on many digital music players - but not on iPods. When you buy a player, look for a model that will play the formats most appropriate to you.

Don't go deaf

To avoid damaging your hearing, follow the 60/60 rule. That's what audiologists recommend.

Your maximum listening time should be 60 minutes a day with the volume no higher than 60 percent. If you listen for more than 60 minutes, you should turn the volume down below 60 percent.

Set the volume when you're in a quiet environment. And don't turn it up to block out noisy environments.

Try this simple rule of thumb ... if you can't hear other people talking when you're wearing headphones, or if other people have to shout at you to be heard three feet away, then the volume's too loud - it could be damaging your hearing.