In word processing programs, people often type two returns to separate each paragraph. In page layout programs like InDesign and QuarkXPress, it's better to create space between paragraphs using the Space Before and Space After attributes in the Control panel or Paragraph panel.
Here are three reasons why Space Before/After works better than extra returns.
1. An extra return between each paragraph is by default a "whole line". In other words, if you are using 12 points of leading in your paragraph, you will have an extra 12 points of leading between your paragraphs. But what if you want 11 points, or 13 points? This is easy to adjust if you are using Space Before/After, and a pain to adjust if you are using returns.
2. Extra returns between paragraphs, in long text, will sometimes end up at the top of a column or a page, moving the text that follows down from the top of the frame, creating uneven tops of columns or pages. With Space Before/After, space is never added at the top of a frame.
3. Using extra returns between paragraphs prevents you from being able to use the Keep Options properly. These handy controls allow you to ensure that subheads always "stick" with the following paragraphs, and never get separated at the bottoms of columns or pages.
To easily get rid of all the extra returns in your text in InDesign CS3 or CS4, choose Edit > Find/Change. Then choose Multiple Return to Single Return from the Query drop down, and click the Change All button.