1-3 are total numbers. Obviously you can make more money and for longer if you constantly update your course or book.

I wanted to provide ballpark figures to give a general idea. Some are from personal experience, othes from friends and people I have helped, and others from general industry knowledge.

Thanks for that! I had a quick look at your website linked from your profile, you've got quite an interesting, varied career.

I'm thinking of self-publishing a book on a somewhat technical topic that's trending upwards at the moment, so this advice is most helpful and timely.

Thanks. Have you looked at solutions to actually produce the book? Unless you're already setup, three nice options are:

1. https://www.softcover.io/

2. https://www.gitbook.com/

3. https://leanpub.com/

Wow this is great, thanks so much again! I'll definitely look into these.