A mattress protector should feel like part of the bed, not like a separate layer you have to “deal with.” A lot of people buy one for peace of mind, and then stop using it because it changes the sleep experience. Maybe it feels a bit stiff under the fitted sheet. Maybe it traps warmth, and you wake up uncomfortable. Or maybe it makes that subtle crinkle sound when you shift. Those are small annoyances, but at night, small annoyances become big ones.