How do I decide which resolution to select when scanning from Epson Scan?

• Resolution refers to how many dots per inch (dpi) or dots per centimeter (dpcm) your image contains. The best resolution for a scanned image depends on the type of image you're scanning. For most images except line art, use a scanning resolution that is approximately one third of your output resolution or a scanning resolution of approximately 240-300 dpi. For on-screen viewing, you can scan at 96 dpi.
  
  Keep the following in mind when you choose a resolution: Higher resolution settings result in larger file sizes. For example, an 8.5 x 11-inch original scanned at 300 dpi can produce a 24MB file. The same original scanned at 96 dpi creates only a 2.6MB file.
  
  Large files take longer to process and print, so consider the practical limitations of your computer system when selecting a resolution. To keep your file size manageable, select the lowest possible resolution that gives acceptable quality. When scanning at a higher resolution, reduce the file size by scanning only part of the image.