I (obviously?) didn't do a long term study. They have some details about their claims here: https://www.allbirds.com/pages/sustainable-practices https://www.al

I (obviously?) didn't do a long term study. They have some details about their claims here: https://www.allbirds.com/pages/sustainable-practices https://www.allbirds.com/pages/sustainable-practices [you can download their report] Most sportswear shoes, "sneakers" in vernacular, don't accommodate resoling. But evenso, the plastic mesh or wool upper (depends on model) tends to wear out in obvious spots (same as where socks might wear out, like toes).