(FORTUNE Magazine) – LAST SUMMER, Allen and Susan Pierce toured a charming hilltop vineyard while vacationing in the South of France. The setting was postcard-perfect: stone walls dating back to the Romans snaked through rows of lush grenache vines, and below, waves of green-gray foliage stretched west to the Montagne Noire. By the time the tour ended, the Pierces were so enchanted they decided to buy the vineyard—well, actually, a half-acre of it. The rest is divvied up among other wine enthusiasts.

Fractional ownership dates back to 1960s time-shares, but NetJets sparked the high-end trend when it began selling shares of planes in 1986. Then luxury resorts got into the act, and suddenly "time-share" wasn't a bad word anymore. Now the range of asset-sharing arrangements aimed at the well-heeled has exploded to include not only vineyards but golf, handbags, jewelry, yachts, and autos. Who are the buyers? Call them the "partsumers": the couple who needs a yacht for weekends in Key Largo, the investment banker who wants a helicopter lift from Wall Street to his house in the Hamptons, or the fashionista who wouldn't carry anything less than the latest It bag. The American dream may be to own, but for this set, luxury tastes just as good by the slice.

"Thirty years ago people had fewer things, which created a lot of attachment and value," says Ravi Dhar, a professor of marketing and director of Yale's Center for Customer Insights. "Now, with the proliferation of options, there's less commitment, and it's 'I'll use it for one year and move on to the next thing.'"

That was part of telecom executive Doug Dunbar's rationale last year when he joined Miami-based Yacht Share instead of buying a boat. A $40,000 membership plus monthly fees gives him 28 days on a captained luxury yacht and privileges at tony clubs such as Key Largo's Ocean Reef. "I'm investing in the experience rather than the asset," he says. Also new to the fractional game: newcomer YachtPlus, which sells one-eighth shares in Norman Foster–designed megayachts for $2 million.

But it's not just about "leveraging" (i.e., leasing days on a posh boat for a fraction of its price). Dunbar and others say they've held enough deeds to recognize the downside of ownership. Besides tying up capital, big toys are costly to care for and depreciate rapidly. "You start to think, 'I'll buy something a little cheaper, a little easier to maintain,' but that's a lot less fun, frankly," says tech executive Phil Hunt, who lives outside Boston. So though he fantasized about buying a finicky Italian sports car, he ultimately chose a dependable Mercedes E-Class sedan. When he feels like taking a flashier car out for a spin, he drops by the Otto Club. (If his girlfriend is in tow, he'll skip the Ferrari in favor of a more comfortably appointed Aston Martin.) "You can't do that if you own just one of them," he says.

Car-club members aren't the only ones test-driving. Purse subscription firms like St. Paul–based From Bags to Riches ship handbags with retail values up to $3,000 to label loyalists around the country. "The customers who use our services most, as far as dollars spent, are the ones who buy four to eight $1,000-plus handbags a year," says co-founder Sam Mangiere. "If they're buying Louis Vuitton or Fendi, they can try out Gucci or Balenciaga."

Noncommittal golfers have Tour GCX, where members pay $6,250 to tee up at 31 private courses without splurging on a full country club lifestyle; commuters can buy fractional helicopter stakes through Sikorsky Shares; and avid travelers have destination clubs, which offer access to luxury homes for a membership fee and annual dues. Though destination club sales rose 43% year-over-year to $726 million in 2005, the industry is still young and volatile (early leader Tanner & Haley filed for bankruptcy last summer). The latest entrant is Tim Blixseth, the man behind Yellowstone Club, a private golf and ski resort near Big Sky, Mont. Last year he launched Yellowstone Club World, which so far has four ultra-high-end properties—and a $3 million initiation fee.

But what's the logical end to all this fractionalization? "Luxury convergence," of course. Jacob Yahiayan, an investment banker, has just launched New York City–based Continental Luxury Brands, where clients can shop for fractional cars, planes, and vacations. After all, somebody has to help multitasking partsumers organize their fragmented lifestyles.

SHARE TACTICS

Beyond time-shares and NetJets, here are seven ways to embrace the fractional life.

Vineyards

Opportunities range from deeded plots (buyavineyard.co.uk) to shares in wine estates (wineestatecapital.com) to vine rentals (3dwines.com).

Cars

Boston's Otto Club offers both individual and corporate memberships (theottoclub.com), while San Francisco–based Club Sportiva has satellite locations in Vegas, New York, and Munich (clubsportiva.com). For fractional ownership, try Chicago-based Exotic Car Share, which ships cars across the U.S. (curvyroad.com).

Golf

A $6,250 Tour GCX membership (tourgcx.com) buys ten rounds at 31 private golf courses in New York, Florida, Vegas, D.C., and Boston.

Destination clubs

Five-year-old Exclusive Resorts (exclusiveresorts.com) leads the field with 300 residences, from Paris to Turks and Caicos.

Yachts

Membership clubs (theyachtshare.com) and lease-share programs (pinnacleyachts.com) supply everything from Sunseekers to Jeanneaus.

Designer accessories

Besides handbags (frombagstoriches.com), some firms rent jewelry with retail value up to $16,000 (bagborroworsteal.com).

Helicopters

This fractional program (sikorskyshares.com) has a ten-chopper fleet with service on the East Coast.