Home and interior design are in a constant, ever-advancing state of evolution. But since humans have sought shelter in caves, the primary purpose of our homes – shelter – has remained constant. And of all the rooms that serve this critical need, none embodies it like the master bedroom – and no single piece of furniture is more critical to rest, relaxation, and rejuvenation as the master bed. Considering we spend almost a third of our lives in bed, our master bed may be the single most important piece of furniture in our homes. Here are some tips to make the right choice for yours. Follow these guidelines, and you’ll sleep easy knowing you’ve made smart choices.

• Start with a great foundation. The most vital part of any master bed is the mattress. Mattresses range in price from a few hundred dollars to several thousand dollars. But no single mattress is right for everyone, and the bed that’s best for you may not have the highest price. Personal preference is key, so be prepared to invest in what’s best for you.

• Try before you buy. Feel intimidated climbing onto a mattress in a store and settling down as if about to take a nap? Don’t: that’s exactly what you should do – and what the staff at any reputable establishment expects. Take enough time to determine whether a bed’s level of support is right for you. When in doubt, opt for the slightly firmer choice. Ever stay at a hotel or resort where you enjoyed an unbelievable night’s sleep atop a bed that was just perfect? Inquire about the make of mattress the hotel provides guests. Upscale chains like the Ritz-Carlton and Westin even offer the mattresses and bedding they use for purchase, for guests who want to experience the same level of comfort at home.

• Know what you’re hopping into bed with. If you’re sensitive to chemicals, play close attention to the contents of a mattress. Research natural options like those using cotton, horsehair (which is hypoallergenic), wool, and down. Many commercial mattresses contain synthetic materials like formaldehyde and polyurethane foam, which “offgas,” releasing smelly and potentially toxic volatile compounds. It’s enough to make anyone lose sleep, which is decidedly against the point when it comes to beds. If you’re bothered by the smell a mattress gives off in the store, steer clear, because it’s not likely to smell better once you get it home.

• Protect your investment. We’ve established a good mattress is not only a worthwhile luxury but an investment as well, so think about purchasing a mattress protector, which guards against dander and is obviously much easier to launder than a mattress. Flipping your mattress every other month, in addition to taking a vacuum brush to its exterior, will also help your mattress stay in top condition.

• In bedding, thread count counts – but only so much. Thread count can be an important indicator of quality, but what matters most is what those threads are made of: specifically, the thread’s fibers. Cotton-polyester sheets may last longer, but all cotton sheets – specifically, those woven with “pima,” “Supima,” or “Egyptian long-staple” cotton – will yield a softer, finer hand. Sheets are often chemically-treated to keep them from shrinking and wrinkling, but sheets labeled “pure-finish” are produced without chemical treatments. What you’ll give up in sheen and longevity, you’ll gain in comfort. Consider having several sets of bedding: it’ll increase the longevity of each set and give you different seasonal options to help change up the look of your master bedroom. If you’re worried about cost, know that bedding doesn’t have to cost a fortune to be fabulous: Jaclyn Smith’s “Today” and “Traditions” lines for Kmart provide smart, sensible choices from the contemporary to the classic.

• Take cover. The main purpose of a comforter is warmth. For this purpose, you may want to have two: one for summer and a heavier one for winter. Down is an ideal choice for an all-season comforter. When properly laundered, down will keep you cool when you want to be cool and warm when you’re hoping for a toastier slumber. Down pillows are also a luxurious place to lay one’s head, but go with a choice that provides the level of support your neck needs.

• Make sure you’ve got a good bedside manner. Now that your bed is outfitted to perfection, the last thing to consider is the bedside table, if you chose to have one. I do, and I keep only the essentials there: soft, incandescent lighting for reading a good book, a scented candle, and my cell phone, which now serves, as it does for many, as my alarm clock. A charger, tucked away so the cord is barely visible, ensures my phone’s just as recharged and ready for the new day as I am.