Adhesives' shelf life directly depends on the storage! The most important thing is to keep glue tightly closed in a dark dry room away from direct sun rays, with the temperature under 68 Fahrenheit. With water ingress, glue starts to harden, that's why some lash stylists put their adhesive into a bowl of rice because rice absorbs liquids. If you follow all the storage rules, your glue will be in a good condition up to 2 months.