Little to no breaking in required. I wore them intermittently for several weeks before a 77 mile walk in Devon, UK. Handled coastal ups and downs, moors and bogs. They got soaked, caked in mud and other things one might find in sheep and cow pastures. My feet inside didn't know any of that. My map reader had the women's version and she swears by them, too. (Alas, she calls hers "cute").