I've been helping devs for 2 years to work better with databases. Switched to full-time consulting this year. The book took a very long time to create. Everyth

I've been helping devs for 2 years to work better with databases. Switched to full-time consulting this year. The book took a very long time to create. Everything calculated together about 400 hours. So yes, I couldnt have done this in my free time. I just took the time this year as this year was planned as some kind of programming sabbatical - a do whatever I like thing. That it was such a great success and paid off all my time is just a bonus.