Yea, this issue never entered my mind until I read this post. I really don't have a viable alternative for storing powder and primers, so I guess I'll keep doing what I have been doing but keep an eye on the powder.I’m not gonna say keeping it inside the house is ok, but that IS what I do.
Most of what I buy, I consume rather quickly so I’m not concerned about it. I do have some powders for loading up ammunition for old family heirlooms and stuff, and I open those and check smell and color 1-2 times a year. I burned a couple of pounds of 4320 last year. Other than that, never had to cull any.
As I said, everything is stored in the original factory containers. Also, my reloading table and component are not near any ignition sources, gas or electric heating devices, etc. Also, rarely does the powder get over 5 to 6 years old before being consumed.