"Sleep," the British novelist Virginia Woolf wrote in 1925, is a "deplorable curtailment of the joy of life."

Today, the same might be said about shopping for a bed.

Or so it's beginning to seem to Jason and Cris Martin, Ballston newlyweds who, earlier this month, committed to replacing their full-size box spring and mattress -- a gift Cris received from her parents five years ago -- with a roomier queen-size model.

Jason, 27, a software engineer with a penchant for nailing sweet deals on cars and stereos, thought the process of selecting a mattress would be a snap. Instead, his dream of finding the right bed has turned into a shopper's nightmare.

Grasping the nuances that set apart the likes of Sealy's patented PostureTech Coil from the Simmons Pocketed Cable Coil has been particularly trying. "It's bizarre," laments Martin. "It seems like the more you learn, the less you know. I never expected choosing a mattress would be so hard."

It's not just the subtle differences that industry leaders such as Sealy, Serta and Simmons use to differentiate their products from one another that's so frustrating for shoppers like the Martins. The vast array of styles manufactured by each Big S -- and marketed aggressively by such major retailers as Mattress Discounters, Mattress Land, Mattress Warehouse and Hecht's -- is stultifying. "How can you do comparison shopping when you're not comparing the same product?" he asks rhetorically.

It's a fair question. But perhaps the wrong one. Many mattresses -- particularly those made by the same manufacturer but distributed to different retailers -- are more similar than they may appear at first blush.

Kevin Damewood, senior vice president for sales and marketing at Simmons, says it's not unusual for various chains to buy the same style of mattress but slap their own distinctive labels on it. More commonly, however, a retailer will request additional cosmetic modifications to help differentiate the product further -- a different color ticking, for instance. But frequently such changes have little if any substantive bearing on the product.

"We make beds that sell from $399 to $4,000," he said. "At every price point [increments of $35 to $50] we make a different kind of bed. It's up to the retailer to select the product that allows them to keep themselves different from the competition."

That's a long-standing practice in the mattress industry that may complicate things for the consumer in the short run, concedes Daniel Butler, vice president of retail operations for the National Retail Federation, a trade association for store owners based in the District. And, one consumer pointed out, it makes it nigh on impossible to hold a retailer to "we'll beat their price on a comparable model" promises. But, Butler points out, by shielding retailers from the kind of excessive consumer pressure that drives many smaller businesses out of the market, consumers still benefit from broader competition.

Which mattress models go to which retailers under which names is generally considered proprietary information and not shared among retailers, according to Damewood and other manufacturers interviewed. But that doesn't mean the information isn't available, unofficially.

Peter Marino, who has written two books aimed at helping mattress retailers ramp up sales, says the information can be gathered by any merchant willing to do the legwork.

Many retailers -- particularly smaller independents eager to go head to head with the larger competition -- will have shopped the market and be able to identify comparable, if not identical, products sold locally. Over-the-phone retailers like 1-800-MATTRES may also be able to provide information on comparable merchandise. If the retailer says he doesn't have the information, the shopper should consider seeking out another seller who does.

Still puzzled about buying a mattress? Here are a few other consumer-oriented points to consider:

* What about the number of coils?

Coils form the heart of a traditional innerspring mattress. But don't get caught up in a numbers game, advises Marino. Especially when comparing different brands. More and thicker coils don't necessary mean a firmer mattress, better support or longevity.

* Which is better for the back -- a hard or soft mattress?

A favorite question among back patients, but one that has never been answered definitively and probably never will be, says orthopedic surgeon Robert H. Haralson, director of medical affairs for the American Academy of Orthopaedic Surgeons. A credible study of the relationship between back pain and mattress type would require extensive X-rays of a patient's spine and expose the individual to excessive radiation.

* When is it time to buy a new mattress?

In lieu of data documenting a link between a new mattress and good health, that decision is entirely up to the individual, says Sam Wiesel, chairman of the Department of Orthopaedic Surgery at Georgetown University. Meanwhile, the Better Sleep Council, a mattress industry trade group that previously set the life expectancy of a mattress at eight to 10 years, recently revised its recommendations to encourage more-rapid turnover. "People's bodies change over time, and their need for adequate comfort and support increases as they get older," says a recently posted blurb on its Web site, www.bettersleep.org. "That's why it's a good idea to compare the mattress and foundation you are sleeping on now to newer models at least every few years." For the record, Wiesel says he's just now beginning to think about replacing the mattress he has been sleeping on for 15 years.

* What's the best way to test a mattress before buying it?

Most mattress retailers will advise shoppers to spend as much time as possible testing a mattress before making a purchase. That means lying on the mattress on your front, on your side, on your back or any other position that might simulate how you use your bed at home. That being said, it often takes much longer -- at least a month -- to know if a bed will be comfortable for the long haul. Haralson's advice: Buy only from a vendor who agrees to take the bed back -- and provide a full refund, no questions asked -- if you decide it's not right. Get the promise in writing, including a clarification of where the rejected mattress must be delivered and who is responsible for the costs associated with returning it.

* What's the story on mismatched sets?

Nary a day goes by when some mattress retailer isn't holding a clearance on mismatched sets -- meaning a box spring and mattress that are not mates -- often at substantial savings. One bit of advice to consumers: buyer beware. Check that any warranty protections granted to a matched set convey to the mismatch. Be sure that the warranty applies to protections granted by the manufacturer as well as the retailer; many manufacturers state outright that their warranties are rendered void if their mattresses are used on different box springs. This may be a marketing ploy to discourage replacement of mattresses alone, but the effect may be the end of any consumer guarantee.

* The rest

Earlier this year, Serta became the first brand to offer mattresses that meet a new open-flame fire-safety standard to be mandated by California beginning in January. All Serta mattresses sold since Jan. 1 meet California's 30-minute open-flame burn test designed to duplicate fire conditions when sheets and bedding ignite, according to a company spokeswoman.

Newlyweds Jason and Cris Martin of Ballston encountered the mysteries of mattress and box spring comparison shopping when they decided to replace this full-size set with a queen.