We recommend getting a touch up every 2 to 3 weeks. If you wait too long your eyelash extensions will fall out and you will require a full set. Your natural eyelashes fall off every 45 – 60 days due to the natural growth cycle and are naturally replaced with the growth of a new eyelash. Other factors such as expsoure to steam or touching your eyes alot may cause the extensions to fall sooner. A touch up is needed to fill in any lashes that fallen. Touch ups average about 45 minutes.