An evergreen topic is one that will be good for years to come. Many topics change over time, making the ebook you write obsolete as soon as the information changes. You can always provide updates but an evergreen topic will be good forever. Some examples of evergreen topics would be “soft” topics such as relationships, home repair, and knitting. These types of topics will be good for many years to come without you needing to make updates or revisions. It is entirely up to you; some people enjoy writing more to keep their ebook up to date. One of my clients is an accountant who loves to rewrite and re-record his material every year.