We recommend that you use the adhesive within 6-8 weeks of the purchase and opening date. The fresher the adhesive, the better the results. You should keep adhesives upright in its pouch with silica bag in a cool dry room. And shake well (about 2min) before each use and shake between each drop. If you have very high humidity and temperature, and you lash a minimum of 4 clients per day, that means you opening a bottle of adhesive quiet often, you should replace the bottle every 3-4 weeks. When you shake a bottle of glue, make sure you remove lid, place glue pin in to the nozzle and shake it this way, this prevents glue go in to the cup / lid.