Since changing over my baking methods, it has taken me a while to find enough information to make up my mind on things. It can be hard to decide what information to trust but common sense can play a big role. For a while, I was worried that I wouldn’t be able to afford gluten-free and non-refined flour baking because some places even said white flour has a maximum 6-month shelf life. Then I was worried that all my flours should have been stored in the fridge or freezer and had gone rancid. Some flours store best in the fridge or freezer, but many are shelf stable. Quinoa should be stored in the freezer if not used frequently, this is something I hadn’t thought of before as I assumed it stored similarly to rice. This link has a whole chart about storage, but the length of time is something I would consider more of a guideline. Nothing is guranteed because you have no idea how they were stored prior and you should check to see how fresh it is (how far away the expiry date is). As long as they are kept air-tight before use, you shouldn’t have to worry about prior storage.
On the Bob’s Red Mill blog, they seem to give a more realistic outlook of flour and grain life span. Another thing you should always consider is that before technology things like grains were stored out with no air-tight containers or possibly even cool storage. Now, wheat poisoning did happen but this was also before the invention of preservatives as we know them. I highly doubt any food has as short of storage as we are led to believe, it just wouldn’t make practical sense. We live in a throwaway culture, food companies would rather you waste more and buy more.
The best thing to do for most things is to just become familiar with the product. For flours, a good practice would be to smell, taste and observe the flour once you open it, then you have something to compare to when you are not sure if it’s safe. Flour weevils are also a sure sign something has gone bad. This article states that freezing for four days will kill weevils and apparently you can use flour like that. I think I’d rather just try to not get weevils in the first place!
Happy Herbivore explains that while many flours will stay just fine without freezing, if you are worried storage in the freezer extends the life to about a year. Unrefined grains have a shorter shelf life, this should be ovious at this point in the game. Whole wheat and rice flours are best stored cold as this slows the oils from going rancid.
You should always try to use your own common sense in these situations though, because that way you can teach yourself and KNOW without having to guess. Keep in mind climate and season because obviously humid weather will impact your food a lot more than cold frigid weather. Most things are just fine for at least a month, after that it all depends on how much you plan to use the item.