I spent about a decade as a technical writer, preparing manuals for publication, so I have found it fairly easy to self-publish some books strictly for my personal use. However, book design is not a skill most authors have, and a poorly designed book is difficult to read, difficult to use and just plain ugly.

Anyone planning to self-publish with a view to selling their book and making money off it is likely to discover that it would be much easier to make money the old fashioned way, by laboring for a paycheck. There are exceptions to this, but it is the rule that writing books for self-publication is not a paying proposition.

Do it because it is fun. (OK, a rather twisted sort of fun, but still fun.)