We've been flying both our American and Blueline flags for 7 or 8 years now. We put them out every morning and bring them in at night. I've found that we replace them every 9-12 months, usually due to fading, but sometimes it's because of fraying.
I do like the follow up emails telling how to fold, preserve, retire them, etc. I am also happy to report that i remembered all of that from elementary school, which was a long, long time ago.