Question: how do i know when i need to replace my running shoes?
Answer: You have new aches and pains. If you notice that your ankles, knees or hips get more achy after a run, it might be time to get a new pair of shoes. ... 
Your feet get extra sore after a run. ... 
The treads are worn out. ... 
The midsole feels tough. ... 
You keep getting blisters or brush burn.