In reply to lm610: I think it depends on the shoe. An unlined shoe will stretch quite a lot but I don't see how the rand can stretch so if there is lots of rubber stretching will be less effective. Similarly with lined shoes they will not stretch as much as unlined. If they are only a quarter of a size smaller than your shoe size I would just give it a bit of time to wear in naturally otherwise it would be easy to overdo it and make them useless in the longer term.