Even as much as I paid for these sheets, I should have known when it said "fits up to 18" deep" that it would't be true. I have a 17" mattress, I did wash the sheets before use, and the bottom sheet fights to stay on the mattress. This is very irritating because the reason I went with a higher dollar sheet set was in hopes of getting sheets that didn't shrink and didn't slip off the bottom mattress. That being said, since we are going to buy a new mattress set in January and we will never have another 18" deep mattress, the sheets should fit fine at that time. They are, as others have said, VERY heavy (hubby likened them to canvas) but are soft. I think we will be glad of the heaviness in the winter but hope by summer they will have softened up in the wash. I am of two minds on the sheets - on the one hand, they are very well made, very silky to the touch, are obviously not a cheap set, and they are a beautiful dark color. On the other hand, I battle the bottom sheet, trying to keep it on the mattress. Would I buy them again - maybe. I won't know until I see if they soften up in the wash and see if they shrink more. Do I like them? Yes, very much. But probably not enough to buy again.