I have my grains in Lock and Lock containers and vacuum sealed bags. I store then in the basement which is cool and dry in the winter, I dehumidify in the summer. I vacuum seal my hops or leave them in the factory packaging and store them in the fridge.
My grains of up to a year old are crisp and taste good. I cannot detect anything missing or off in the beer from them. My hops, also up to a year old, seem to give the proper results.
I also have frozen yeast, some over a year old. 8 or 9 different strains.