Sometimes a spare room isn't enough. We all know that changing your zip code to a warmer climate magically multiplies your roster of would-be visitors. And when people who already had a wide circle of family and friends move to Sarasota, they often decide that adding a guest house is more necessity than indulgence.

Some Southwest Florida guest retreats are even multi-tasking, accommodating visitors during tourist season-November through April-and serving other functions at other times of the year, from housing a college-age son home for the summer to providing a home office or place for meetings. There are as many reasons to have guest retreats as there are people who will happily occupy them. Just ask the owners of these three Sarasota guest houses why they love these useful spaces.

Nantucket On Her Mind

Interior designer Anne Folsom Smith was in a Nantucket frame of mind when she recently refurbished and updated the guest cottage she and architect husband Frank added to their bayfront property seven years ago. The result is a 900-square-foot coastal casual retreat that is fresh, charming and oh, so inviting.

Whitewashed paneling, exposed beams and pickled oak floors established the bones of the concept. Crisp periwinkle blue, soft white and accent colors that remind guests of wildflowers became Smith's palette. For an understated window treatment, the designer installed light-filtering textured shades that seem to melt into the wall color. Two daybeds in the living room area are done in simple blue-and-white mattress ticking and piled high with blue and white pillows in a pattern that references the linens in the bedroom. The designer chose wooden painted chests as coffee tables, giving guests extra storage.

She added flowers and foliage, too, voluptuous bouquets of blue and cream hydrangeas, a glass jar of daisies here and there and a large tropical plant to fill a corner of the living room. But all the foliage and blooms are faux, so that a guest never has to feel a responsibility to water anything or dispose of wilting flowers.

For the bath, Smith found a vintage dresser, cut out the center and dropped in a basin to reinforce the cottage look. Ceramic drawer pulls and cabinet knobs in the kitchen have a yellow and purple butterfly motif and provide whimsical art against the snowy kitchen. The hexagonal table and chairs are painted white. She used blue and white tiles for the backsplash and the kitchen counter. Several pieces of artwork were done especially for the cottage by local artist Kay Curtis. She also provided the hand-painted wooden orchid signs that lead travelers from the main road to the Folsom Smith property.

The owners refer to their guest quarters as a carriage house, since it's perched atop a vine-covered, detached two-car garage. The large L-shaped space has a pitched roof that ascends to 14 feet in the center, an open floor plan and is on two levels. The bedroom and bath area are a few steps up from the kitchen/living room space. A narrow screened balcony off the living room offers visitors a glimpse through the tropical foliage of Sarasota Bay.

The cottage is in use nearly year round. Anne's mother arrives every Christmas for a few months. Frank's three children frequently come with their families, and friends come and go on a routine basis. Frank also offers the carriage house as a place for visiting architects to stay while they are consulting in Sarasota. "And don't forget us," says the designer. "A couple years ago when Frank and I were having some work done in the main house, we moved into our carriage house and had a little vacation. It was like being in another world. A nice world."

A French Affair

From the beginning, Lynn and Bill Elstein's 1,000-square-foot guest bungalow was a family project. The owners imagined what the space would look like, and their contractor son-in-law, Dan Maglich, built it. Now all the children and grandchildren get to enjoy it. "Actually, most of the time the little ones stay in the main house with us," explains Lynn. "Their parents take the guest house and have themselves a mini-vacation."

Just like the 13,000-square-foot main home, the guest house expresses itself in the French language of design. Areas in the main home are done in Paris Bistro (the kitchen), Art Deco, Provencale, and Lavish Louis. For the guest quarters, the family selected a French West Indies theme because it's casual, comfortable and addresses an aspect of French culture that is nowhere else on the property. The guest house faces the swimming pool and has large bathroom that opens out onto the pool pavilion. The facade of both guest house and main house are in a country French manor style, ornamented with wrought iron detailing.

A stylish black and white toile pattern depicting idealized West Indian life establishes the palette for the gathering room and bedroom. Flashes of parrot red and fern green are the accent colors, playing upon the warm richness of the exposed beam ceiling and the wood and wrought-iron furniture.

Because Lynn Elstein is a fine cook-she's studied in France-she took special care with the kitchen, making sure it was outfitted with everything a vacationing chef could want, including a dishwasher. "We had to find a custom, scaled-down version to fit neatly under the counters," says the homeowner. "And I was really surprised to learn that the smaller ones cost more than the full size ones." Imported hand-painted tiles add art and practicality to the kitchen backsplash and countertops.

"Before guests arrive I stock the refrigerator and the pantry with breakfast essentials and things for snacks," she says. "The rest of the time we're all eating together." The floors in the guest retreat are easy-care stone, and in the bath the same stone was tumbled for an accent trim in the shower.

Since the guest house was completed three years ago, the Elsteins have entertained guests from California, New York, New Hampshire and all parts of the South as well as grandchildren from right down the street. "Their favorite thing is to make up a basket and take a picnic to the guest house," says the grandmother. "So off we trudge out the back door, around the pool over to the guest house. It's a big adventure for the children. And every time I'm in that pretty place I think to myself how absolutely delightful it is. If I were my guest, I'd be quite content there."

More Than Meets The Eye

When a hip Chicago couple in tune with modern art and architecture decided they needed a guest house, they turned to architect Jon Potvin. The couple lives in a gated community with strict architectural regulations that are anything but sympathetic to their modernist leanings, and Potvin had managed to negotiate the rules and please both the homeowners and neighbors.

He did the same with the 1,200-square-foot guest house. It appears stately and traditional from the street, but it's thoroughly contemporary and jazzy inside. Best of all, while this sleek retreat is a self-contained vacation residence for out-of-towners, it's also a gym for the homeowners and includes treetop office space for the wife, who is a consultant to the food industry. This luxurious dwelling really earns its keep.

The guest house took about a year from design concept to the final coat of paint; and as soon as it was ready, the homeowners relocated their exercise equipment to a room between the new structure's bedroom and bath. As they work out, they enjoy a view of their garden and a nature preserve. The house also includes a compact built-in kitchen with high gloss cabinetry that maximizes space and was custom scaled to tuck neatly into the wall.

The two shopped for furniture locally and also moved a few existing pieces from the main home or storage. The black low-slung Italian leather sofas and Noguchi table were from the husband's bachelor days. A classic Herman Miller cherry and metal table that transitions from dinner to a corporate conference table in seconds used to be his law office desk. New pieces include an Asian-inspired television armoire and queen-size bed.

The upper level is the wife's office. From her computer or upholstered window seat, she's been able to watch eagles nest and monitor the progress of their fledglings. The office is outfitted in painted and stained natural wood furniture from Ikea. The wife grew up in Arizona, and a homey touch is her extensive collection of Southwestern kitsch artifacts, including "sleeping Mexican" figurines and cowboy lamps.

Although the rooms are sparsely furnished, a feeling of luxury and warmth is achieved with sophisticated materials, such as the golden hued Jerusalem limestone for the bath, rich mahogany window frames, silk pillows and chenille throws on the bed, art lighting and light bamboo floors.

The couple enjoys discovering regional artists at charity auctions and on weekend excursions. Their guest house is a gallery for paintings they continue to acquire in St. Petersburg, Tampa, Miami and the Sarasota area. They often switch artworks from the main house to the guest quarters to maintain a feel of changing exhibitions.

"The contrast between light and dark woods, the white walls, the high-impact art and the lighting combine to make this guest house architecturally dramatic as well as fully functional," says Potvin. "Viewed at night from the main house, it's a glistening jewel. In fact, it's so enticing that the homeowners tell me they occasionally steal away to the guest house to treat themselves like VIPs."