Dry boxes work well to keep ammo in. When stored in a climate controlled facility they will probably work well for your entire life. This is assuming you were born this year or later. Just placing ammo in the original container on a shelf in the house will probably be still good to go many years from now.
I am considering getting some dry boxes to put reloads for the range in. They might be easier to carry that way. Factory ammo is the only thing that stays on the shelf very long. I only shoot it when I need to add cases for reloading.