Eyelash extensions are where an individual false lash is applied to every one of your own natural lashes one by one. The result is longer, fuller looking lashes which have a huge effect on how you look! Mascara is no longer needed!
The extensions can last anywhere between 2-6 weeks depending on your natural lash cycle and how well they are cared for.
Natural lashes have a 30-90 day cycle. So when the natural lash is ready to fall out it will take the extension with it. After a while there will be gaps in which you can come get refills if you like.
This link has some Q&A about eyelash extensions:
http://www.xtremelashes.com.au/eyelash-extensions.php