If you buy indicator silica gel, it is reusable; you just wave it or bake in regular oven to drive out the accumulated moisture, when dry, it changes color - when wet again, it changes color, to so indicate.
I personally and from long experience shooting in hot humid environs (e.g., Shikoku) think that putting anything cold or cool in a cooler w/ film or camera is a bad idea unless it is in its' own double bagged ziplock with silica in the outer bag ; condensation is a killer!