I have a bottle of Gorilla Wood glue that hardened in the bottle. I called the Gorilla 800 number and she told me that glue ,in the bottle, lasts 1-2 years and further was able to tell me that my bottle was 3 years old, so I guess it's best to check the date before you buy a glue, (although I can't find any date on my Titebond glue.) Anyway, despite my glue being beyond its useful life, the Gorilla people are sending me a coupon for a new bottle. I did not ask for that, pretty good service from the Gorilla people.