I am currently doing this. I am much more productive compared to having a corporate job, but it is really hard on your family. There seems to be an arms race on doing everything for your kids these days. That means moving to a good school district (usually in very expensive places), paying for and driving to tons of activities, organic food, nice stuff. I have realized none of these things are possible while we are living off savings.

That said I feel much happier now being able to focus on a project that is my own creation. I was frequently angry everyday I had to split my time between paid work and my own project, leaving even less time for my family. (To be honest, in terms of total work, I got more done, but was miserable.) I frequently think about the consequences if my project ends up being a failure, but if I never tried to create something on my own, I'm pretty sure I would regret it on my deathbed.

My advice is to do this engineering leisure time before you have a family to support.

<shamelessplug> If anyone wants a preview of what I'm building, please check out https://solveforall.com/. It's a hackable search engine that can be enhanced with user-provided data, programs, and third party APIs. I'm currently working on making it much more customizable and private, so hopefully I'll be able to publicly announce it in a 2-3 more months. </shamelessplug>

One problem as mentioned in another thread is that it is very hard to get feedback while working alone. Everyone is so busy these days caught up in the rat race and their families, and I don't blame them. It would be nice to have some tech friends at work to bounce ideas off of. If anyone has any feedback for me, I'd greatly appreciate it!