answer:Mine balls up a little, but I much prefer that to other that just have a strap like thingy at the corners and the mattress pad just was a rectangle/square that sat on stop of the mattress. How often do you wash the mattress cover? I only do it about 3 or 4 times a year. Is that awful? For years I didn’t even have a cover, so I figure washing it is way ahead of having a mattress for ten years that never gets washed.