When getting eyelash extensions for the first time clients routinely ask.. “ When should I come back for a lash fill?” On average I recommend 2-3 weeks after getting your eyelash extensions applied. A fill for 2-3 weeks out at Lethal Lash Beauty is 60 minutes. Everyone’s shedding cycle for lashes has many different variables. A large component is how well you care for your lashes. If you are avoiding oil around your lashes, brushing your eyelash extensions daily, and keeping your eyelash extensions clean they will tend to last longer. You should have 50% or more of your eyelash extensions still intact in order for it to be considered a 2-3 week fill. At 4 weeks out you should at least have 40% of your eyelashes still attached from your original eyelash extension appointment. This appointment is about 75 minutes. If you have less than 30% of your eyelashes at your appointment it will be considered a full set. To ensure you get in when you are in need of a fill be sure to schedule your next appointment before you leave.