Don't Crop the Joint said Rich Despins, our lecturer on one of the most common editing tools. There are many reasons to crop, but generally it is to make a better, more impactful image. You need to plan ahead when composing to leave enough space around the subject for cropping but not too much that resolution is reduced. A common reason to crop is to remove distracting elements, perhaps a tree branch or too much sky. A more creative reason is to change the aspect ratio of an image, make it square or panoramic or vertical instead of horizontal. Be careful where you crop. Generally we avoid cropping people but if you must, don't crop through a joint like a knee or elbow. Also leave enough room if the image is going to be printed and displayed in a frame. Sometimes you want to leave context around a main subject. Try to emphasize this through the title of the image so judges don't automatically say you should have cropped tighter.