Every time I write up a tech tip, I take screenshots. I get emails every week from my colleagues asking how to perform a certain task, and when I respond, I use screenshots. Without a dedicated tool, screenshots can by kind of a pain, but they can be extremely useful as a visual aid.
The dedicated tool I use is ZScreen. With it, I can select particular portions of the screen, include the mouse cursor (surprisingly important to do), and have the shot automatically load in my image editor of choice. If I then choose not to edit the image, it automatically ends up on the clipboard, meaning I can then paste it into anything that will accept an image. All of the screenshots I take are saved in folders by date, so I can recover old ones without having to recreate anything.
ZScreen is a free download.