I carry a flapjack bar; the shelf life is good: however, it is best to check best before date & know how long you have before having to consume. N. B. Depending on maker, the sugar content can vary from 27g to 34g (Olyke Foods Oat Flapjack Original: 27.1g; Lottie Shaw’s Traditional Oat Flapjack: 34g).I am currently using Olyke Bar; purchased three months ago; use by date: 20/01/2024.
Also, I rarely consume whole bar in one sitting: I divide into eight portions & consume 2-3 pieces.
Regardless of manufacturer, one whole bar is equivalent to an actual meal in it self: check calorie content!