If you do the eat what you store, store what you eat thing, you can actually avoid the need for most long-term storage.
If, however, you're storing against a rainy day or TSHTF, then you'll need to do more long-term approaches.
Flour isn't a long-term prep; you'll have to use it up. In the right conditions (no oxygen, cool storage, out of the light) you might get a few years out of it, but nothing like you can get out of rice, beans, wheat, even dried milk.
One of the best ways to do long-term storage is in mylar, with an inert-gas atmosphere. Sometimes people will use dry ice to purge oxygen from a bucket of food they're storing, a few have a way to nitrogen-flush, but most people use Oxygen Absorbers. Since the atmosphere is almost completely Oxygen and Nitrogen, in a sealed storage environment binding the oxygen to the absorber leaves an almost perfect Nitrogen atmosphere.
Many of my own preps are put away against a big SHTF scenario; some I am rotating. I have buckets of rice, wheat, beans, dried milk, popcorn; all are stored in mylar bags in 5-gallon buckets.
The mylar bag is about the only reasonably-priced method for getting a good hermetic seal; if you just use food-grade buckets w/o mylar, the seal may or may not be good over time, and if you use O2 absorbers, they will create a partial vacuum in the bucket as the 21 percent of the air which is oxygen is bound to the absorbers. That can cause the bucket to collapse a bit (or a lot, depending), so in my case I don't put on the lid until after the mylar bag has collapsed against the food.
You've made some great steps in preparedness, and now that should give you a bit of peace of mind as you consider your next step.
