Lash extensions give the appearance of having mascara on without the messy clumps and smudging of makeup. Generally, a single lash is applied to each natural lash. When applied properly, neither the eyelash extension nor the glue should touch the eyelid because it may cause irritation. This was designed to last until the lashes naturally fall out, which is usually around 2–3 weeks. After those 2-3 weeks, new lash growth will need to be bonded, making lash extensions a biweekly service if one wishes to maintain the full look.