It'll last for years with its high salt content. It's made from fermented fish, so can't go off any more! But don't keep it in the fridge or it may form crystals. Just a cool dark place. If crystals form, warm and shake the bottle to dissolve them. If the container is plastic - beware! It may become brittle over time and crack very easily, and the last thing you'd want is fish sauce all over the cupboard or floor!