A friend of mine has been wearing the Chaco Z2 for years. After a trip to see him again I was convinced to try it. They are so simple, all you have to do is loosen or tighten them. The pressure of your foot as you walk pulls on areas that are too loose or too tight. So they are always perfectly balanced. I can't stand flip flops. I don't like midfoot wrap sandals. I've never felt safe in them. But these, well, there's a reason they're river shoes, not even a river can take them off their feet. Last I get miles from them and they wear very little. I think they will do for 500 or 1000 miles of walking. I read that some people claim to be 16 years old. Therefore, despite the cheap price, I have no doubts that when the time comes I will buy identical replacement parts. Enjoy!