Why Print in Black?
If you just print occasional emails, webpages, and other documents, you probably don't need to print in color. If your print-outs come out with extraneous images and coloring, you're spending more money on printing than you need to.
Color ink cartridges are generally more expensive than black ink cartridges, and, what's more, some printers refuse to even print in black and white if a color ink cartridge is empty. Printing in color when you don't need to results in needlessly spending more on ink.
Obviously, if you print a lot of photos or other color documents, you will probably want to keep printing in color. Of course, when you need to print photos, you can selectively print these in color, so you can still save money on other documents.
You don't need to remember these steps; just set your system up once and start saving money on every document you print.