I have 2 flavors of Critical Care, Essentials for Life, and Lifeline. I keep it all on hand because it's a lot easier to grab it from your kitchen than it is to run around in a frenzy when you're worried about a sick chin. Some vets carry Critical Care (mine does), but I only have one chin that will willingly eat it for me, while all seemed to like EFL. The Critical Care has an expiration date on the bag (1-2 years, I think), and I've read that storing it in the freezer extends the shelf life, so that's where I leave mine. I keep the Lifeline in the fridge next to my probiotics, but I don't recall how long it lasts for. I'm sure someone else has that info for you.