The conditions that affect the flag on your flagpole are like fingerprints - No two are alike. Even Flags on adjacent poles do not necessarily receive the same effects of the "same" weather; a building may partially block some of the elements of the weather from the flag on one pole while the flag on the pole right next to the first pole, may get the full force of the weather. Maybe the flag is too close to a structure and when the wind is right, the flag touches ofr hits the structure causing damage. Just being out in the sun affects the material.
The flag is made of high quality outdoor fabric, BUT IT IS STILL FABRIC, not "miracle" material so the elements of weather, location and usage all affect the life of your flag. So we can not answer you question of "how long will my flag last??" BUT what we can do is help you find ways to extend the life of your flag.
Here are some things that you can do to help yourself and to help extend the life of your flag.
Finally, here is a tip to always have a great appearing flag on your pole and to never be put in the embarrassing position of not having a great looking flag ready to fly for that important visitor that's arriving in 3 hours or tomorrow morning at 8:00am.
When you have used flag #3 to replace 1 or 2, then you can order a replacement flag, without panic or incurring overnight shipping.