Misaligning your images or text by several millimeters might not look like much, but a watchful eye could catch your mistake - and suddenly put your work in an unprofessional light. Professional editors often spend hours before production making sure everything is all lined up and ready. In the old days, this meant using your eyes (and a ruler) to make sure the plates were properly aligned. This method did not always work well, and caused the slightly skewed words and pictures you sometimes see in older publications.
We live in the digital age now, and Scribus has some tools to keep your borders exact and the columns lined up. The Guides feature can produce vertical and horizontal lines that object edges can be "snapped" to and held in place. Let's look at an example below: