Eyelashes have a lifespan like any other hair follicle on the body, and each hair cycle varies from person to person.  

For the most part, its around a month long.  Now, when an extension is applied to a natural lash, the natural lash continues to grow.  As it grows, the extension is still attached.  

Imagine painting your nails, and as your nail grows longer, the polish moves out with the nail. This is similar to how lashes operate.  Imagine the nail polish is the eyelash extension.  So because of this, the extensions need to be replaced every 2-3 weeks to avoid this lash grow out.  If the extensions stayed on the natural lash, they can get too heavy on the end and twist or pull. 

During a fill, a lash artist goes through the lashes and removes any grown-out lashes, as well as any that are ready to come off.  Then the lash artist replaces the extensions with the appropriate length lash throughout the lash line to fill in the lashes and create a full, voluminous set. 

We highly recommend that all clients get fills at 2-3 weeks.  After 3 weeks, it’s common for gaps to begin to be more visible and the lashes not to look as full.  

To get the most out of your investment, it’s important that you book lash fills regularly. 

In short, lash extensions last around 3 weeks before they need a fill.   Yours may last longer, but the fill appointment may take longer after 3 weeks or you may require a new full set.  Always ask your lash artists what they recommend for fills and if possible, book in advance.