There is a new brand of CA, Mercury, that claims to have an extended shelf life backed by a replacement guarantee. I can't speak from experience since I just received my first batch of the stuff, but it does sound promising. As for the old stand-by brands, refrigerator or freezer works to store unopened bottles, but once opened that's a No-No since moisture (in this case, condensation) will accelerate the hardening process. But, an unopened bottle will last for several years in cold storage, based on my personal experience. And if you use the odorless (aka foam safe) CA, expect a much shorter shelf life and slower set-up time than regular CA.