CHICAGO — Diane Pyshos collects houses.
At the moment, she and her husband, Bill McCollom, have three. The couple and their son, Thomas, manage to live in all of them, although daily life can be complicated by errant clothing or grocery miscalculations.
"One house has five mustards and the other houses don't have any," Pyshos jokes. "You forget which house you're supposed to go to."
Not that she's complaining. The family loves its self-described schizophrenic existence, which revolves around two homes in Michigan (five miles apart) and one in Chicago. Now, the family's thinking about a fourth residence, in Arizona.
They may be on to something. Thanks to a confluence of demographic and economic factors, owning two homes is verging on the commonplace, according to gatherers of real estate data. And now, some number crunchers are starting to scrutinize the ranks of owners of three or more homes.
"We call them 'supersplitters,' " said Bill Jacobs, a demographic analyst in Seattle. Jacobs' firm studied second-home ownership for WCI Communities. The term "splitters" is used to differentiate an emerging profile of second-home owners from the more traditional "snowbirds," who tend to divide their time seasonally.
Splitters, on the other hand, are likely to bounce between homes, relatively speaking. And supersplitters, with three or more homes, elevate that practice into an art form.
Their numbers are nearly impossible to peg. Public property records and lenders' data don't tally how many properties a buyer owns or even how the homes are used. Some third properties are investments, others are for personal use and still others are a blend of both.
Also, a revival of interest in timeshares and the creation of so-called fractional ownership of vacation properties have put the term "our third place" on many more people's lips.
Clearly, these changes have the potential to move multiple-home ownership beyond the confines of the super rich and into the ranks of the "economically comfortable."
They're out there. "Income is tilting toward the top end of the scale," said Peter Francese, a demographer in Exeter, N.H., who added that if third-home ownership isn't entirely mainstream, it's getting closer.
"One-fifth of all households take home 50% of all the money in this country," he said. "So, multiple homeowners might have a ski condo in the winter, a summer place on a lake and a regular house that they live in the rest of the time. It's a small segment, but significant."
In WCI's national study of 1,743 homeowners, 20% own a primary residence and second home, and 9% own a primary residence and at least two other homes.
"We were surprised at the incidence rate," he said. "It was higher than anyone expected."
The National Assn. of Realtors last year estimated that there were about 44 million second homes in the U.S. -- about 7 million private vacation homes and 37 million investment units.
But the definitions can be a confusing tangle: The association also estimated that 10% of those investment buyers intended to use their second properties at some point for recreational purposes.
The trade group reported that in its study of people who bought second homes in 2004, 38% said it was very likely they'd purchase another residence within two years.
"It's absolutely a real phenomenon," said Francese, a trends analyst for Ogilvy & Mather and founder of Ameri- can Demographics magazine. "There are a lot of reasons why it's happening."
Possibly the biggest driver of third-home ownership has been record-low mortgage-interest rates, coupled with a growing affinity for real estate as a long-term investment, he said.
"An awful lot of people are skittish about the stock market, but real estate, that's viewed in the general public as a sure thing," Francese said.
Then there's the bumper crop of baby boomers who not only are in their peak earning years, but who also might be flush with equity from the primary residences they bought as long as three decades ago, and they're looking for a place to put it. They're also at an age when vacation homes may also double as retirement destinations.
Technology plays a role too. Expanded air routes have put more vacation destinations within reach, and telecommuting -- to keep in touch with the office, if not to work full or part time -- makes it possible to stretch regular weekends at a getaway spot into long weekends, or more.
Brooke Warrick, whose California firm, American Lives, studies consumer behavior for the real estate industry, said he's skeptical of the growth potential of third-home ownership. "I think there's going to be a backlash, in terms of second and third homes," he said. "People are going to understand that owning these things is a lot of work."
But others say the real estate industry recognizes the potential for such disenchantment and is trying to build in support services to shoulder the maintenance burden.
Such service comes at a price, of course, although it's one that many in the housing industry say consumers are willing to pay.
The Urban Land Institute in Washington, D.C., expects the second-home market to remain solid for another decade, but third homes are likely to remain just one of many niches that have emerged in housing in recent years. For one thing, the federal tax structure permits deducting mortgage interest only for homes No. 1 and No. 2 if they're strictly for private use. The expectation is that fewer people will be willing to pay full freight for a third house.