I haven't worn these for a full day yet, but I wore them around the house for an hour or so, and they are very comfortable. Truly, they require no "break-in period." The only thing I noticed was that they tend to be quite narrow (I bought my usual size, 8.5W, and it's just barely wide enough), and the heel strap seems flimsy. Otherwise, though, they seem like very durable shoes, and I have never been disappointed with a pair of Clark's.