I purchased these sandals for my vacation to Rocky Mountain State Park and the Grand Canyon. They were comfortable from the minute I put them on. I did a lot of walking for many days in a row, and the temperature was between 90 and 100 degrees every day. My feet stayed cool and comfortable. Now that I'm home I wear them almost every day after work to run errands, etc. I also have tendinitis in both feet, and my feet never, ever bothered me even after all the walking I did.  Excellent product.