When I first started running I got the prettiest shoes I could find in a size that was available and fit me well enough. Silly girl. After rolled ankles, strangely sore muscles, and a few days of not being able to run at all, I have learned my lesson. Take it from me, there is a difference between shoes that work and shoes that do not.
Most running guides recommend getting new shoes every 300 to 400 miles, or every six months. If you do more than just run in your shoes- Zumba, kick boxing, etc., then replacing your shoes every six months could be the wiser measurement. Old shoes are one of the leading causes of sports related injury. You may need to replace your kicks or try a new type all together if you have any of these issues.
Bruised Toe Nails
Unless you are running marathons and mid training for Iron Man, there is no reason your toenails should get bruised. Having bruised toenails or nails that fall off is a sure sign they need replacement. Even shoes that once fit like a dream can start to hurt our little piggies since fibers are wearing down and your foot is not getting much support.
The heat caused while running cause our feet to expand in the shoe. If your shoes are too tight or fit snug while resting, the constriction while running could be causing the bruises. Likewise, too loose of shoes can create a lack of traction and cause bruising from your foot sliding forward and back. To stop this from happening, pick a shoe that fits loose in the toes but snug in the heal. This will leave enough space for the toes to move and keep your foot from sliding while running.
Rolled Ankles
If your foot rolls inward or outward while running, your shoe is not pulling it's weight in the support department. Rolled ankles can range in severity from not bad at all to a break or sprain.
Shoes that give more ankle support will have wider bases and be higher around the heal. A good comparison is the sole of a Puma vs. the sole of a Nike Running Shoe. Most Puma shoes are made to be slim and lightweight with a small sole that rolls up into the shoe and has a very small heal. These are no good for support.
The Nike shoe, on the other hand, has a broader sole that is wider than the actual shoe and has a heal ridge that rises higher than the laces. These are the type you want, especially if you are are doing exercises that encourage side-to-side movement.
Sore Arches
One of the quickest ways to know if your shoes have moved on to greener pastures is the strain your foot feels after a workout. Once the shoe starts to break down, the arch support will go. If the top of your foot or the muscles in your arch are hurting, your foot is not getting the support it needs. This can be fixed with a few different methods.
People who have high arches may need added support, even in new shoes that fit perfectly. If this is you, try shoe inserts made for high arches. These are usually pretty cheap and will cushion the foot while keeping your arch supported. The best thing to do is bring a pair of inserts with you when shoe shopping. Most foot inserts make the shoe a half a size smaller. If your shoes are a bit too big, this could solve that problem as well!
For those who have had their shoes a while, getting a new pair may be the best option. Sure, a foot insert could help for a bit, but the fibers in your shoe have begun to break down. This will make the shoe less supportive over time.