I was wondering if some of the flavors I've had for a long time were okay to use. I don't think they harm you if old but here's what The Perfumer's Apprentice said about shelf life. Hello Karen! I recommend using these within about 6 months! You can greatly extend shelf life by limiting the number of times you open the bottle. Cheers, Bill Brewer The Perfumer's Apprentice & The Flavor Apprentice 170 Technology Circle Scotts Valley, CA 95066 (831) 704-7342 www.perfumersapprentice.com If you have any other questions he got back to me pretty fast.