I haven't had a shoe as comfortable as these in I don't remember when.  First day I had them, I just put them on to check fit, ten hours later I took them off to go to bed. No break-in required. The only problem I have with them is that they are tight to put on.  I have high arches and really have to shove and use shoe spoon to put on.  But the ample toe room and cushy insole more than make up for the trouble.  Size seems true and doesn't squeeze anywhere.