I mentioned it in my review of the
Salomon Speedcross, where I talked about
heel drop.
This is super important when you do anything extended on your feet relating to running (even though walking requires a specific type as well).
In high school I ran distance, when my knees, ankles, hips and lower back hurt I thought it was because I was just getting a workout in that area. That's not the case.
Every shoe has a "mileage" that can be put on it, just like tires. Except with shoes the material, the heel drop, the stiffness, etc really matter, especially if you are having pain when walking and/or running.
If you are having issues with with pain or are just looking for an edge in performance, you should seek out a running shoe shop or a doctor who will have a treadmill and can record you walking and running, along with an XRAY (though its not really necessary but still good to have eventually). They will conduct a
Gait Analysis and then recommend to you, in writing, what your preferred shoe description should be, with heel drop range, and a dozen other points to consider.
When I was really heavy into running I would go through a pair of $150 New Balance running shoes every two months, but I was running more than 200 miles a month and they were rated for about 450 miles. I would feel my knees hurt and my ankles ache after a while and I knew it wasn't me, it was the shoes. I got a new pair and I didn't feel the aches and pain anymore.
This is one of the reasons why I really like Salomon shoes, and my current EDC
Adidas Terrex Fast-R. Zero pain until they get to about the mileage point.
How do you know when the mileage point is up without keeping track? Well, you will probably start feeling a lot of pain if you are standing on them for most of a day or go run two miles, the pain will likely be unbearable in your joints.