Most people find a dealer by looking up "Garage Doors & Door Operating Devices" in the telephone directory or on the Internet. Though some of the companies might manufacture their own doors—particularly wood doors—most buy garage-door sections from large manufacturers.

Some local dealers sell only one manufacturer's doors; others sell a variety of makes. It pays to do your homework before talking with dealers by contacting major manufacturers and requesting product information so that you can compare features. Then contact dealers in your area.

Though some garage-door companies have showrooms, most will send a salesperson to your home to discuss your needs, show you brochures from the lines they carry, and measure your old door.

Some home improvement centers sell a few makes of garage doors that are designed for do-it-yourselfers to install. If you buy a door to install yourself, be sure that it comes with complete and easy-to-follow instructions. Also be sure that the door comes with an extension-spring containment kit in the event a spring snaps—without it, such an eventuality can pose a serious danger.