Well i live in a tropical zone, on the Tropic of Capricorn, our summers are up tp 108*F , and a humidity of 94%. My bottle of Zap sits on my work bench, and was opened 14months ago. I fitted the applicator tube to the bottle when i opened it, and have never had a blockage , or any sign of it going offIn my modelling time i have used 9 bottles of it , and always use to the last drop without refridgerating or any other sort of container. So i feel yours should last a long time also .
Bill, Down-under in Aistralia.