Mark Scheuer has never been one to post a sign that cautions, “Look but don’t touch.” At his Sutter Street linen shop, he’s often found rubbing a sheet between his thumb and forefinger and urging customers to “just feel it!” He’s certain they’ll come to the same conclusion he has: There’s more to a high-end sheet than thread count. Scheuer has honed his knowledge of home textiles for bed, bath, and beyond over 30 years in his family’s business, which his grandparents, refugees from Nazi Germany, started in the 1930s by selling linens door to door. His parents and grandparents opened their first shop on Stockton Street in 1953, and the family relocated the storefront to its current location 15 years ago. Here, Scheuer tells us how to dress our mattresses—no princess and pea required. Scheuer Linens: 340 Sutter St., S.F., 415-392-2813, 800-762-3950, scheuerlinens.com

It’s the new year, the traditional time for linen sales. How do you determine when it’s time to throw out the old and bring in the new? Typically, a well-cared-for sheet lasts about 50 washes or around four years. Wear is determined by how many sets of sheets you have and how you treat them—how often you wash them and the way you clean and dry them.

How many sets of sheets are optimal? Three sets per bed in the household: one on the bed, one in the closet, and the third in the laundry. The same goes for towels.

I’m afraid I’m guilty of abusing my sheets. How do you care for yours? We recommend Le Blanc linen wash, which has a neutral pH. It’s the best and safest product you can use. Avoid bleach or excessive heat in the dryer, and you shouldn’t let sheets sit in the dryer. That adds wrinkles and makes them harder to iron.

I thought I was the only one who still irons sheets. The wash-and-wear era really spoiled people. Nothing replaces ironing. If a customer says, “I don’t want to iron,” I can’t sell them a single thing. We only sell one polyester-cotton sheet that wrinkles less easily, but even that needs to be ironed to appear perfectly smooth.

Do you iron your own sheets? I send them out to Hol­iday Cleaners on Polk Street. It’s the only laundry in San Francisco we recommend.

When I was growing up, there was nothing but percale sheets on the market. Now, sateens dominate. What’s the difference? Percale is made using a plain weave: The yarns are interlaced with a regular over-and-under pattern. It has a matte finish and a crisp feeling. The sateen weave is created by an under-one, over-four pattern—though it could be more than four. Then it is calendared, or passed between rollers, which may be heated, to create a smooth finish. Sateen’s silky feel and shiny look can seem more luxurious and can cost more.

You call thread count a “marketing ploy.” To prove it, you bought 20 different pillowcases from vendors you don’t carry. What do they show about different fabrics or linens? That Sferra’s Grand Hotel’s 200-count collection feels better than a 1,500-count case that we tested from Linen Source. Some people perceive a 1,020-count sheet as feeling heavier than sheets with a lower count.

Then what does make a great sheet? The finest sheets start with a longer staple of cotton fiber, usually around 1.5 inches. The longer the staple, the more the cotton can withstand the force of spinning without breaking. Egyptian cotton is considered best because it produces the longest, smoothest threads. It’s based on a longer fiber and is softer and more durable. But other factors also contribute to quality and feel: the spinning process that produces the yarn, how the yarn is woven into a fabric, and how the fabric is finished.

How can you tell if your sheets are made using a long staple, or even how a fabric is finished? You can’t. None of those things are listed on the package. Maybe one day, sheets will have the same labels as foods.

Where are the best sheets made? Italy and Switzerland. None are made in America anymore.

Your most expensive sheets are $1,330 for a solid sateen queen set by Sferra. Why so much? Giza 45 is considered the world’s finest super-long staple-cotton yarn. To date, it has been used only by a handful of shirtmakers. The fabric created with this fiber is the lightest, softest, and most luxurious sateen available, and Sferra is the only company to transform that fine fabric into sheets. But you don’t have to spend nearly that much to get excellent quality. We also offer a line by Celeste—it costs about $475 for a queen set. It has a crisp feel typical of percale cotton and is one of the best values in our store, using price, feel, and dura­bil­ity as criteria.

Why is it that I go to a hotel and always love the sheets? Either the hotel is using a better set than you are, or it’s psychological—the bed is made up for you, the sheets are pressed and look fresh and luxurious.

You encourage people to feel before they buy. How can they, when sheets are packaged and most stores don’t provide swatches? You can’t—and you have no idea how that sheet will feel after it is washed a couple of times, let alone 25 times.

So, buyer beware—there’s nothing you can do? Most department stores have a liberal return policy. If you really don’t like a sheet after a washing or two, return it. We certainly accept that here.