Winter can be tough on carpets. Here are a few things you can do every day to maintain your carpet's appearance and a few things you should know before hiring a professional cleaner.

Daily care. The best way to protect your carpet day to day is to remove your shoes when you get home. But don't go barefoot; your feet have natural oils that rub off on the carpet. Those oils act like a dirt magnet, so it's a good idea to always wear socks or slippers.

If possible, vacuum your carpets daily to remove surface dirt and dust. Use a vacuum with a HEPA filter and change the filter every six months so you don't blow pollutants back into the air.

Professional cleaning. As far as deep-cleaning your carpets, of course you want to clean them if there are visible stains, but the Environmental Protection Agency recommends a professional cleaning one to four times a year, depending on how heavily trafficked the area is. A professional cleaning removes not only the dirt and stains you can see but also what you can't see. Carpets are like indoor sponges, trapping all types of pollutants, including dust, mold, bacteria, and mildew, that can be bad for your health.

When hiring a professional cleaner, choose a company that uses hot-water deep extraction — it's the most effective way to clean your carpet. Professionals spray the carpet with a cleaning solution and then use high-powered machines that emit hot water at high pressure onto your carpet to loosen dirt. At the same time, a high-powered vacuum pulls the hot water out of the carpet, along with the dirt and soap.

There is a huge power difference between professional carpet-cleaning machines and those you can rent at home and hardware stores: Professional machines have a pressure measurement of 250 to 1,200 pounds per square inch (PSI), as compared with the machines you can rent, which have a 35 to 70 PSI. A lack of powerful pressure could leave a soapy residue, which will then dry and attract dirt.

Reputable companies typically give you a price per square foot in a written proposal; usually it's between 50 cents to $1 per square foot. If you talk to a company that gives you a vague quote or a low-ball price, beware that there may be extensive overcharges once the cleaners are in your home.

Spills. Act quickly, says Andrew Ross from Triangle Legacy, a carpet-cleaning and flood restoration service in the Washington area. Use a white cloth or towel (the dye from a colored cloth could rub off on your carpet) to blot the affected area. Do not rub, or you will just push the stain in deeper. "You can use a little water on the stain but not too much — you don't want to douse the stain, or the water will seep into the carpet pad and will take longer to dry and also possibly mildew," Ross says.

Most important, "don't wait to call a professional," Ross says. "The longer you do, the more the stain sets in."