I decided to give these shoe liners a shot after reading the reviews online. I wore them for several hours while out dancing and they stayed put perfectly. The sticky part in the heel worked wonderful and no part of the liner was exposed outside my ballet flats. However, I could see how the liners might stick out some in the front if your shoes don't completely cover your toes. I wear a size 9 1/2 and ordered the M/L size shoe liners, seemed to be more or less the correct size. Would recommend the S/M though if a 9 or smaller as the heel of the liner had some extra room.