A: Lash Applications are temporary, using glue that can be removed with warm water and cleanser. The lashes used for this application would be strips, flairs and individuals. These take minutes to apply. Lash Extensions are applied with surgical glue that will keep the extension on for the life of the lash it is attached to. A full set takes up to ninety minutes to apply, and a fill-in every two weeks is recommended, which is about a 45-minute appointment.