If you are creating a large document like a book, you want to build in the most control you can, so that if you need to change something, you don't have to re-do everything. The use of styles will help you with this. Make your text with paragraph styles, and if you have variations (like a body style and a body style that needs bullet points), base similar styles on master styles. That way, you just need to change (for example) the font size in the body style, and it will apply to all of the text that the body style is applied to, along with styles based on the body style. Also, if you want variations within a paragraph (like bolds, italics, color/font/size changes, etc.), use character styles.
What this all leads to is that if you have your text keyed in in another program (like Word), and it's already formatted, yes, importing Rich Text will save you from formatting it all over again, but if the Word file is built with styles, you are that much more ahead of the game. Even if you don't like the way the text is styled in Word, you can build styles in InDesign with the same names as the Word styles, and upon import, choose whether to convert the Word styles to what you have in InDesign.
Returns will not get lost if you import RTF or TXT or DOC(X).
But what I strongly recommend, don't use imported styles at the end. You might or might not import them. It depends how accurate your document was done in Word.
Make all your styles in InDesign and never use multiple returns, multiple spaces or any manual formatting. Use Paragraph and Character Styles.
So is it a bad idea to import a RTF instead of plain text because I might accidentally import text with extra returns, spaces etc. ? I didn't create the original file I am importing so I'm not sure if this sort of thing might be in there. I know about and use the paragraph style option etc. in InDesign. I guess I am just trying to figure out why it is considered best practice to import plain text and not rtf (based on all the how-to videos I've seen) Thanks for your help!
You are totally overthinking this.
How are going to even know what should be what if you bring in plain text? Even a poorly formatted Word file can be fixed up fairly easily using the tools in InDesign. Find/Change is your friend. Learn how to use it.
lol I'm good at doing that! I think you are right. I just finished formatting my first book series and am about to embark on my second. I think the trauma of learning all of this the first time around (and screwing up a bunch) has made me too wary. Thanks for your help!