If you get lash extensions you should invest in some lash shampoo.
Washing your lashes and maintaining them will help you keep your lashes lushious! Good maintenance means less coming in for fills. 
 
Directions:
Pump ince into your palm or onto a brush.
Apply to your lashes and lash line in a gentle back and forth motion
Rinse throughly with water and PAT dry (with a non fibrous towel).