Congratulations! If you are planning to keep your current home for many years, any improvements can be more about your own enjoyment and less about what a future buyer will think. Savor the freedom of creating precisely the house you desire—but keep value in mind too. Even if you never move, your heirs will thank you.

Consider large-scale improvements in energy efficiency. You can reap considerable savings while you live in your home, and the green upgrades will make your residence more attractive to future owners. When remodeling the kitchen or any other room, Stukel points out, "since you've got the walls open, it's a crime not to spend a couple thousand more for insulation." Most older Chicago-area homes especially will need a thick blanket of insulation in the attic or basement. It can cost up to a few thousand dollars, says Stukel, a green remodeling aficionado, but will reduce annual heating and cooling costs by 15 to 30 percent.

With a long horizon, big-ticket items such as solar-heated hot water (about $5,000 after tax incentives) or geothermal heating and cooling ($10,000 and up –see "The Nation's Greenest House, Three Years Later") are less daunting. But first, improve your home's ability to hold in heated or cooled air, suggests D'Arcy. The more you can reduce the energy load, the smaller and less costly any new alternative-power equipment will have to be.

As Stukel notes, if you are contemplating major green improvements, it pays to prioritize. Energy Impact Illinois rebates for efficiency upgrades (such as insulation) are set to expire in 2013, while a federal 30 percent tax credit for solar installations runs through 2016. "Do your efficiency in the next two years," she says, "and solar in four."

Plan for your needs as you age. "That's very important," says Scott Sevon, a co-owner of the Palatine-based remodeling company MAW Chicago who chairs the National Association of Home Builders' committee on aging in place. Rather than face the pricey prospect of refitting the entire house all at once when the need strikes, factor accessibility into any repair or home improvement along the way. For example, when replacing old doors, Sevon suggests, look for new ones that do not have sills; these ease the passage of people in wheelchairs or with other mobility concerns.

Similarly, any bathroom remodel ought to include a shower without a sill. Grab bars, low-set sinks and countertops, and flat-panel light switches that don't demand finger dexterity can all be installed incrementally. And if you don't have a full bathroom on the first floor, consider putting one in. 

Pay attention to kitchen lighting. "In too many kitchens, you have lighting in the middle of the room, and it's behind people when they're working at the counter," Sevon says. Task and undercabinet lights allow people with diminished vision to prepare food safely—and lend some stylish panache to the room at the same time. (For more renovation tips, visit ageinplace.org.)

Reconfigure spaces or make additions to accommodate multiple generations. That's what Jonathan and Carolyn Singer did when they brought her aging father to live with them and their two children in their house in Highland Park. In 2010, they created a new master suite in the attic, freeing up the old master suite for him; a second phase of improvements, completed last December, added a first-floor family room, another bathroom, a mudroom, and a second-floor workout room. Now the Singers have settled in for the long haul. "We're not planning to go anywhere," Carolyn says.

Jonathan Rubenstein, the Highland Park painting and remodeling contractor, is a big fan of the kind of flexibility the Singers have built into their house. He especially likes rooms that can serve more than one purpose over time, and so do his clients. "They don't know what's coming in their lives," he says. The Singers' workout room, for instance, could become a bedroom or an office; that second master suite, which accommodates an aging relative now, could suit some other family configuration down the line. Because if the real-estate market has taught us one thing over the past ten years, it's that you never know what the future might hold.

EDITOR'S NOTE: The online version of this story has been updated from the print edition to correct a factual error.