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

• Resolution refers to how many dots or pixels per inch (dpi) or dots or pixels per centimeter (dpcm) your image contains. The best resolution for a scanned image depends on the type of image you're scanning and your final output device. For most images except line art, use a scanning resolution that is approximately one third of your output resolution. For example, use a scanning resolution up to 100 dpi with a 300-dpi laser printer, and up to 200 dpi with a 600-dpi laser printer. For high dpi ink jet printers, such as the EPSON Stylus Color or Photo series, use a scanning resolution of approximately 240-300 dpi. For on-screen viewing, you can scan at 72 dpi.
  
  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 72 dpi creates only a 1.3MB 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 the image and cropping or removing the unneeded empty spaces.