Storing flour is a bit of a crap shoot. I've had some flours that were stored in the paper bag for 3 years that were perfectly fine, while I've had others carefully packed away in airtight containers that had bugs in them in 6 months.
I'm not a big fan of ziploc bags for flour storage. Ziploc is permeable enough to let odors seep in as well as to let moisture out and dry out the flour. I'm a much bigger fan of food grade plastic buckets with lids. I've asked for buckets at the bakery in my local supermarket twice now and both times they had a large bucket (4.25 gallon) waiting to be recycled.
A lot of members freeze their flour before storing it- that helps extend the shelf life by killing off insect eggs. I've been mulling over using dry ice to store the flour in CO2, but so far, it hasn't been necessary. Storing All Trumps in plastic buckets in the basement, I use it up before any issues arise- that's usually around 8 months.