If you’re looking for a case for your mobile phone, or some new headphones for your iPod then this word will come in handy.
Here you can see the word in use at a mobile phone accessories stand in Taiwan:
The sign reads 瑞驛（瑞驿 ruì yì）which is the name of the shop, followed by 手機（手机 shǒu jī ）”mobile phone”, and then lastly 配件（pèi jiàn）”accessories”.
Here it is again in use on the Apple website:
Just like the English “accessories”, 配件 can be used for all sorts of things, such as 電腦配件（电脑配件 diànnǎo pèijiàn）”computer accessories”, 衣服配件（yīfú pèijiàn） “clothing accessories”, 汽車配件（汽车配件 qìchē pèijiàn）”car accessories”, so it’s clearly a very useful word.