Why do i keep wearing out my walking shoes?  

Do you have flat feet? What I mean by that is do you have a curve in the middle of the bottom of your foot or is it just flat?
My husband and son both have flat feet and they both go through shoes like crazy and it is because when they walk their feet arch inward because there is no curve and it is wearing down that area.
Do you ankles seem to lean inward at all even if just real slightly?
If this is the reason your shoes are getting worn down so easy, there are insoles that can help. Of course there are ones that you can buy at the stores but they don't work as well, trust me we have tried. But there are ones that any foot doctor can get for you...what they do is take a cast mold of your foot and then make a cast of it, cover it with padding and you wear them in your shoes. What it does is supports your foot so your not wearing at whatever side you are..
They do work really well, and it is best to do it this way from the doctor that way it will be specialized to your foot and will be more fitted and comfortable for you.
Best of luck :)

This is definitely from the way you walk. It has nothing to do with your shoes!

For me, I always wore out the soles at the balls of my feet first. I am in the process of correcting this. Here are some of the things that I have been doing that are helping me:

*Stretch your legs daily. Take a few minutes each morning and each evening to gently stretch your legs. This will keep the blood flowing and the muscles loose. (As an added bonus, it also makes you feel better overall!)
*Get a massage of your legs. This will help loosen your muscles that are overworked. It will also make it easier to retrain your muscles as you change how you walk.
*Pay attention while you are walking. Does you heel hit the ground first? Do your toes it the ground first? Are you walking with the insides of your feet hitting the ground first? A good way to see where you put pressure on your feet is to walk through sand. You can then see the footprints. The parts of your footprint that are the deepest in the sand are where you put the most pressure on your feet! Try to be conscious while you walk so that you put pressure evenly on your whole foot.

Correcting the problem with your shoes will take some time. You will also notice the difference in your legs - especially your lower legs - as well as your feet.

I'm wondering the same thing! I just got my tennis shoes last year, about the spring of last year and they barely made it a few months without me wearing a huge hole in the back of my shoes. I really do not want to spend $50 on a new pair of shoes so I'm trying to hold out on it for as long as I can.

Because of my school, I walk most of the places that I go so with all the walking it's understandable that I wear out my shoes so fast but I can't believe that it happens as fast as it does. I do think I have flat feet so if that is it, then maybe I need to correct that somehow. I can't afford to keep spending money on shoes!