You spend 2,920 hours a year on your pillow. What it's made of is not a trivial question.

Cotton pillowcases hold heat. They absorb moisture and keep it against your skin. They cause friction, which matters for hair breakage and skin texture. Linen is temperature-regulating — it stays cool in summer and warm in winter because of how its fibers breathe. It's naturally hypoallergenic and mold-resistant. It softens with every wash and lasts decades. But here's the spiritual argument: the way you sleep is the way you rest, and the way you rest is the way you recover, and the way you recover is the way you show up. Caring for your sleep environment is not vanity. It is maintenance of the instrument.