There are several reasons to generate a clean EPUB.

• Consistency. Consistent styles to maintain the same look and feel across platforms.
• Simplicity. With fewer interactions between CSS styles, changes are easier to implement and track.
• Human readable. Easy to find chapters, sections and styles.
• Convertible. Simple styles lend to consistent conversions between formats. Creates Microsoft Word documents with fewer embedded Styles.

Of course, there are disadvantages.

• Investment. Generating documents requires time and effort. However, since the the styles are reusable, the level of effort for future releases is reduced.
• Technical knowledge. This requires more than a passing familiarity with Markdown, XHTML, CSS, and Calibre. However, there is pleny of documentation available online to help.

While the disadvantages can dissuade people from experimenting with this capability, I found it simplified my eBook submission process. I can target Draft2Digital, Google Play, and Amazon Kindle, using one EPUB, and maintain advanced formatting like realistic text messaging throughout.

This tutorial focuses on features Calibre offers to make EPUB management easier. These tips and tricks may prove invaluable for debugging an eBook in the future.