hi hitzan! glad you like running trails, and i do it occasionally too, especially when the wildflowers bloom... it's beautiful! but after 31 years of mostly road and treadmill running, i have to say that it's done fine by me! there is a lot of variety among runners, no doubt about that.
i do alternate between two pairs archy... mostly for convenience though. i keep one at my office locker room for lunch runs, and another at home. my asics seem to fail (like clockwork) at about 400 miles though, whether i'm running one or two pair. but knowing when your shoes need to be replaced is a key thing for all runners... when they feel flat and unresponsive, it's a good time to start looking for another pair of shoes. keeping your shoes fitting well may help you avoid injuries down the road.