The most important issue in buying a scanner depends on your needs. The demands of photo processing and optical character recognition (OCR) are quite different. You don't want to throw money away on features you don't need, but it's not worth saving a few dollars if the scanner can't produce the quality you require.

If you're primarily interested in storing or faxing printed pages, or turning them into editable documents with OCR software, a sheet-fed scanner will save you time and money. Look for these features:

Speed. The faster the scanner works, the more work you can get done. Check out both the speed of the scanner and the quality of the software that turns documents into faxes or editable text. See how many steps you have to go through.

Resolution. Look for a resolution of at least 300 dpi and 256 levels of gray. Some inexpensive scanners may offer only 200 dpi scans, which is all right for faxing but problematic with OCR software.

Software. Look for a good document management program. The best of these will let you scan a document and decide immediately whether you want to fax it, store it, run OCR or import the image into a graphics program. They'll also catalog and categorize the scanned files on your hard drive.

Physical setup. How big is the scanner? Does the paper feed from the front or the top of the unit? Does that fit in with the way your desktop is arranged? Can it fit between the keyboard and monitor (a convenient location for scanning text documents)? Find a scanner that will fit in comfortably with the way you work.

Portability. If you want to use a scanner with more than one computer or take your scanner on the road, be sure to get one that hooks up to your USB port. If you want to take your scanner on the road, shop around and find one that's small enough to fit in your briefcase.

If high-quality images and color graphics are important to you, get a color flatbed scanner. You can also use these for faxing and OCR. Here's what to look for:

Resolution. Get a scanner that can capture at least 400 dpi and 24-bit color images. Unless you're producing separations of color photographs for a professional printer, the money you pay for higher resolution may be wasted. Also remember that high-resolution color images can gobble up many megabytes of disk space.

Speed. You'll find a great variation in how long it takes different scanners to process pages. Some do everything with one pass of the scanner head, while others require multiple passes for color work. Get a one-pass scanner if speed is critical, but make sure you're not sacrificing image quality.

Software. Most scanners come with programs that control the unit and allow you to do some basic image editing. But the better scanners come with additional graphics programs that give you more control over the finished document. A capable program packaged with the scanner can save you from having to buy additional graphics software.