Bitmap vs.Vector
Image Formats

Let's start with the obvious:

Keeps the glass of your flatbed scanner clean. Don't use Kleenex or other cleaning materials that may leave lint or specks on the glass (or worse, scratch the surface)

Check and inspect the document you want to scan. Clean it before put on your scanner.

Be certain the image you want to scan is nice and straight, that way you won't have to crop that much.