That's a loaded question, palexaides.
Is the container truly tightly sealed? Were is the container stored? Is the area in which it is stored air-conditioned? What is the humidity level like where you keep it? How much flour do you use in a day, a week? Is it plain flour or self-rising flour?
In an ideal world, if the container is really, really tightly sealed, lives in a climate-controlled environment and quite a bit of it is used frequently, I would say your flour would be fine.
In my own pantry, I have probably close to 30+ pounds of assorted flours: cake, bread, all-purpose, rye, wheat, utility "bench" flour, granulated flour (Wondra) and self-rising flour and have no problem keeping it for months. However, I make ALL the bread products we eat in this house, which means the flour gets used up quickly and replaced regularly. The only flour that might be suspect is self-rising, which would lose its leavening capabilities if stored improperly and/or for a long period of time.
I also live in a non-airconditoned house in a climate that is extremely hot and humid during the summer months. I store all my flour in large Tupperware containers.
This is my take on your question. I'm sure you will get many more answers. Just be patient and help will arrive.
In the meantime, I would be interested to hear your answers to the questions I posed.
"As a girl I had zero interest in the stove." - Julia Child
This is real inspiration. Look what Julia became!