So I got a new pair of nice New Balance's in the middle of July and I've put about 320 miles on them so far. For the past week and a half or so, my right knee and the in-step of my feet have had a decent amount of soreness/pain after a run and I've had to scale back my miles per week from around 30+ to around 20. Runs over 4.5 miles start to really wear on me when I usually churn out 8-11 miles with a decent amount of ease. They're definitely starting to feel a little less cushioned. Is this a pretty good indication that I need a new pair of shoes? Thanks.
I've read that how long a shoe will last is somewhat proportionate to your weight. Heavier runners should expect about 300 miles or less and lighter runners about 600 miles. I would submit that the quality of the shoe affects these distances greatly as well. I consider myself in the heavier category and only have around 200 miles on a pair I purchased in May. The cushion seems to be waining some, but is still adequate to give me a decent runs. However, the right heel is missing some of the rubber, so I'm at the end-of-life on this pair.
Since your performance and comfort are being affected, it is time to get a new pair, but keep the old pair for a week or two and try alternating between the new and old. This will tell you right away if it was the shoes or something else.
I agree with HTH, and would also like to add, that as time goes on, you may need additional support in the shoes you do wear. I recently had an extensive fitting at a reputable running store, and found that my needs have changed since I started running ten years ago. I recommend going to a really good running store and have someone who knows running fit you.....its worth the time.
When you alternate between shoes, you give them a "rest" to recover, after constant pounding, to their original shape. They will both last longer than if you bought two pairs and used the pair A every day and when they wore out used pair B. Alternate them daily (if you go for daily runs) (ie. Pair A Monday, pair B Tuesday, etc.) to get the most useful likfe out of them.
alternating between 2 different pairs of shoes also changes your biomechanics slightly. this can help to prevent over-use injuries as well as letting the shoes "recover"
A good tip is too put the date you brought them with a marker, When 4-6 months is up, change them for a new pair.
They say most trainers are good for 500 miles, also if you are buying a new pair dont worry about getting the same model, I loved my new balance 854 and kept buying them, until they disappeared
if you alternate between different pairs , you will feel the difference faster between the "used" ones and the new. You will find out yourself if you need to change / to buy new...