The rule I usually hear is 300 miles or 3 months, but like anything that is just a guideline. For my high school athletes, I recommend every season, and use them only for training. Take your old shoes and use them for gym class or mowing the lawn. A lot of people get turned off by that idea because it sounds like a lot of money, however having a daughter who is training to be a professional ballerina I have a different perspective on the importance of footwear. A worn out pointe shoe can create a serious, possibly career ending, injury. A worn out running shoe may not create an acute injury like that, but over time it will have the same impact on a runner. So ... instead of going by a specific time or mileage, I would say always be aware of your feet and legs. As soon as you start to feel that little nag of shin splints, or some knee/ankle pain after a long run, or even if the bottom of your feet feel sore and a little tired, check your shoes. Squeeze the heel and the the sole of the shoe and see if it is losing its cushion or stability. Everyone is different too. My daughter breaks down her pointe shoes every few weeks where other girls can go a couple months. No one knows your bodies needs better than you do, so my final answer is ... if you feel like you need new running shoes go get them! A little money spent now may save you a whole lot of pain and recovery time down the road. All the best!
The old rule of thumb use to be to get new shoes every 500 miles. Now, how often you should replace your running shoes depends on the type of shoe and your running style. If you're in light or minimal shoes, you're going to need to replace your shoes more frequently than in traditional or maximus shoes. Listen to your feet, if you're loud foot striker, you're shoes are absorbing a lot of impact, and your shoes are going to wear out faster than if you have a quiet foot strike. The best way to tell if you need new shoes is to listen to your body. If your knees, feet or back are starting to feel your runs more, but you haven't changed anything else, it's time to get new shoes! Transition slowly from old shoes to new shoes to give your body time to adjust to the changes. Alternate between old shoes and new shoes every other run for one to two weeks. Happy shoe shopping!
This depends on a lot of factors. your footstrike, your size, your mileage. Big guys often go for well built Brooks stability shoes (like the classic "brooks Beast") as long as the tread is good, you are golden for at least six months. Most people are not running 100 miles a week so you will want to run in a way that works with your life.
People who can run in Nike Frees can get a good amount of mieage, as these tend to wear well and not go dead as soon as, for example,an Asics gell shoe (Asiics feel amazing out of the box, but loose it after a few months as the gel compresses in the typical gel shoe, rendering it into a brick on your feet.).
If you run in an urban environment with a lot of cement and pavement,and are a fairly lightweight underpronator, go for the new Nike free distance. I love this shoe. It has the cushioning of a lunar but the flexibility of a free. if you are a neutral underpronater, this is a good choice. I am a big fan of the Saucony kinvara as well. A bit more stability than the free and a good alternate .Very good traction for rough weather days, though the upper is not waterproof.
I switch shoes for terrain and feel, extending the work life of the shoe and accomodating for different conditions. If you wear the same shoe all the time, I believe you are at greater risk for overuses injuries due to linited movement patterns. Go shopping and mix it up a bit.
The answer to your question is - You can buy new running shoes as often a you can afford them! If you mean to ask how often should I change running shoes? that's another matter. Here is my advice - have at least 2/3 pairs of shoes that you can alternate using for training and for racing. The old rule that you change shoes after 300/500 miles works if you only have one pair of shoes but having more than one pair will allow you to keep your shoes longer!