Considering how many hours you spend in your bed, it might be overdue for an upgrade. First, the mattress: the most common bedding mistake people make, says Zee, is not replacing it often enough. Most can last about five to 10 years; if yours is sagging, it’s probably already past its prime. When buying sheets, make breathability the top priority. “Your body’s temperature changes as you move through different sleep stages,” says Zee, “so you need sheets that can handle the fluctuations.” go for natural fibers like cotton and silk, or try the new high-tech bedding made from moisture-wicking fabrics, such as sheex (sets from $159; sheex.com). The right pillow— down vs. poly, flat vs. full—is also key to nighttime comfort. For a customized fit, try the pillowology line (from $130; sleepnumber.com).