Pillow cases showing stains from normal wear after one week of use and after having been washed.  I go to bed with my face and hair clean but the oil (I guess?) marks on the dark grey don't wash out so the pillow cases look dirty and stained when they are clean.  I'm assuming the sheets will too just with normal use.  The material is very shiny so maybe that's why?  I'm also finding the sheets to not be breathable although the reviews say they are.  These are the most expensive sheets I've ever owned so I am very disappointed.