I'll try this again. I've not heard of a specific number of years triox is good for. I have found that after a few years ( 5-10) that some of them turn to powder. These same packages also
fall apart at ther corners. It's a good habit to check the manufactured date as well as the out date. Often on military items this info will be found on larger boxes, not each individiual package. PM me if you need any more info, I can check the triox I have.