The advantages of dynamic styles are so great that you will never want to go back to manual formatting once you have learned how to use them. They will speed up your work, make it more efficient and make your finished product look more attractive and professional. If you wish, it is quite possible to use only manual formatting in your Help+Manual projects. However, if you do this you will create a lot of unnecessary extra work for yourself and your documentation will not look so good.
When you format text manually you have to go back and change everything manually whenever you change your mind about how you want a headline or a paragraph to look. This can take hours in a big project, and since it's boring and repetitive work you are also likely to make mistakes. Also, when you format manually you will often apply slightly different formatting to text passages that are supposed to look the same, and your work will look messy as a result.
Suppose your client or your boss says that they want to use Verdana 16 point instead of Times Roman 14 point in the topic headers. With styles all you need to do is change the definition of the heading style, which takes a couple of seconds, and all the headers in your entire project are updated instantly.
You can think of a style as a named formatting definition for either text or an entire paragraph. When you use styles you have a separate style for every different type of paragraph and text in your project. For example, by default normal body text paragraphs are normally formatted with a style called Normal, and the topic headers are normally formatted with a style called Heading1. You can define as many other styles as you like for other purposes.
Once you get the hang of it, working with styles is much faster than using manual formatting. To format an entire paragraph you just select the style in the menu, or press the hotkey combination for the style, and all the formatting is applied immediately. You don't even have to select the paragraph. And all new text and paragraphs you type from that point will also have the selected style until you change it.
Since your styles are predefined all your formatting, indents and so on will be identical, giving your projects a uniform and much more professional appearance.
If you have the Professional or Server version of Help+Manual you can save all your styles and your other project layout settings in a special format file called a "skin". When you publish another project you can apply all the styles from the skin to it by selecting the skin file in the Publish dialog – all the styles in the project with matching names will then be replaced by the styles from the skin.
See Transforming Your Output with Skins for full details on this.
Help+Manual's styles aren't just dynamic, they also have dynamic inheritance. This means that styles based on other styles automatically "inherit" the properties of their parent styles. All properties that you do not change in the child styles are dynamically linked to the parent style.
This means you can create families of styles in which you can change properties throughout the entire family just by modifying a single parent style. See About inheritance in styles for full details on dynamic inheritance and how it works.
Note that using styles efficiently can also make your output files quite a bit smaller, particularly in HTML-based output (HTML Help, WebHelp, Visual Studio Help, Windows Exe and ePUB eBooks). Manual formatting must include a large number of detailed tags every time it is applied – in extreme cases these tags can use up more bytes than the text itself. Styles are only defined once and are applied with a simple and very brief reference to the internal stylesheet.
Text Formatting and Styles (how-to instructions)