[JohnFen]

My opinion on this is just that -- mine. This is what I've found works for me, and I in no way assert that it works for anybody else.

If I intend on embarking on a side-project with an eye toward commercializing it, I quit my day job immediately. I cannot divide my attention between two serious endeavors like that, and as long as I'm thinking of, and treating, it as a "side project", I won't give it the time and attention it needs in order to have a chance of success.

I do want some money stored up for the purpose first (forever separate from my regular life savings), and if I don't have that then I'll delay starting work on the project until I do. That said, it shouldn't be a huge amount of money. Too much money gums up the works and reduces the odds of success. I want enough of a war chest to make the venture possible, but not much more. I need to be broke enough that I'm carefully considering expenditures and revenue, and to have enough risk and fear to keep driving me through the inevitable hard times. It also forces me to seek some kind of revenue stream as soon as possible, which I've found is good for the project in many, many ways.

I need to go into a venture hungry and scared.

[Nair0]

I personally am of the same opinion that I, and honestly most people, can't focus on two serious "time sinks" at once, it's bound for one of them to get less attention in the long run and maybe even failing at both if enough bad decisions are made.

I didn't ever consider your other statement though, and it actually makes so much sense. When I quit my job I had so much saved up and still thought it might not be enough, still being on the edge on whether I should wait more or not. But since I knew I had enough, I made a lot of mistakes in my first project, didn't pay enough attention to inefficient code, which eventually made me pay roughly 8 times more than I should per month on some backend infrastructure. I'm honestly just now realizing that the thought of knowing I had enough saved up was probably what made me work so inefficient at first. I fixed most of those issues after some time, but I think that's really sound advice to keep in mind moving forward.

[Bender]

I quit my day job immediately

I think that is smart for other reasons in addition to those you mentioned. I've seen plenty of articles posted to HN where people were sued by their former employer claiming that their corporate time and resources such as intellectual property were used in the production of the product. It often turns out to be false accusations but the wasted time and money from the legal battle is not worth it. Leaving the employer first may preclude such shenanigans.