Rothy's do not stretch. They will fit the same from day 1 to day 365. There is no break-in period. Rothy's will gently hug the contour of your foot but they should never feel tight. They'll move with you, but not stretch out. If they are a little snug but not painful, wear them around the house (not outside!) for a day or so to see how they will give. After a day, if your shoes still feel too snug, we recommend going up a half size.