Are your windows leaking air? Are they getting more difficult to open? Is the wood frame rotting?
Homeowners choose to replace their windows for a variety of reasons, from energy efficiency to esthetics.
"It might be the seals have failed or the wood has rotted," says Kerry Haglund, senior research fellow at the Center for Sustainable Building Research at the University of Minnesota.
Homeowners might be looking to replace leaky windows to keep heat or air conditioning in, or they might want added UV protection to protect furniture from fading in the sunlight.
No matter what the motivation, new windows can be costly. "They're too expensive to think you're going to get your money back either in terms of energy savings or when you're selling your house," says Kit Selzer, a senior editor for Better Homes and Gardens.
Still, new energy-efficient windows can make your home more comfortable in winter and summer and more attractive.
Haglund recommends choosing the most energy-efficient window you can.
The cost for a new window can range from hundreds of dollars to $1,000 or more, depending on the frame, style - double-hung or casement, for example - and whether you choose single-, double-or triplepane glass. Decorative elements can add to the price.
A casement window might be a good option in windy areas, says Gary Pember, vice-president of marketing for Simonton Windows. "As the wind increases, they become more efficient because of the way they seal."
A double-hung that opens only from the top might be a good choice for someone looking for increased security, he says.
Older homeowners or those who think they'll stay in their homes as they age might want to consider a window they don't have to lift.
Frames come in wood, vinyl, aluminum and other materials.
Wood frames are more traditional but require regular painting.
"If you're wanting something maintenance-free, you can't get anything better than vinyl," Pember says. There are many options for vinyl frames, including a variety of colours. You can also get a wood interior and a vinyl exterior.
Selzer says aluminum frames are more contemporary but also more expensive.
While Haglund urges homeowners not to scrimp on energy efficiency, she says there are other ways to save money short of full window replacement.
A new window can be fitted into existing frames that are in good condition.
Or, she says, you can replace just the sash - the part of the window that contains the glass. Again, this would only work if the frame is in good condition.
If you decide not to invest in new windows, you can increase the energy efficiency of your existing ones: "Storm windows are certainly a good idea," Selzer says.
Use caulk or weatherstripping to seal any leaks around the frame.
Insulating draperies or other window treatments also can help increase comfort. "They're so much more tailored and thinner than they used to be," she says. "Old insulating treatments were very bulky, like putting up blankets. Now, they're certainly sleek and more effective."