It depends.

Are the websites about something that may go away? I mean, is it about recipes for the most recent culinary trend? Or strategies about whatever is this winter's trending shooter game? Or programming on a language that may start to die in 5-10 years? Or a framework that everybody will drop in 6 weeks?

It's hard to predict something that generates X income from visitors today will keep generating >= X income in the future.

Is your revenue mainly from Google or something like that? I have heard quite a few stories about people suddenly having to change ad networks and then having their income drop. Or Google changing something in their SEO algorithms and then the site dropping. I even remember reading something about Facebook making a change that stopped most of the organic visits to a specific site. Are you subject to that?

If any of the cases above might be true, I would pretty much only quit my job if I had "can retire in a few years" income.

In hindsight, I wouldn't be OK with passive income from websites, because Google controls your business.

I quit making very little. Now I make over $2000 in passive income, but I wouldn't do it the same way.

An algorithmic change means you lose your livelihood (or income). It's a single point of failure that you can't rely on.

Rather some customers with lots of capital. That's more secure.

$20k / month

Yeah exactly, I'd think it would need to be more than my current job because there's a lot more risk involved, such as losing the incoming revenue if the product fails. Side projects are definitely not as stable as a job is. Plus, if it's passive, why not work and do the side project to make even more money?

Yeah, completely passive income is mostly a dream for most except some extreamely lucky. I think these mostly claiming they do have passive income don't count worrying about project future, taking laptop for holidays just in case, legal risks, upfront investment or just doing tons of small housekeeping or side marketing as true activity. That especialy when passive income becomes the main one. It is optimized business.

If it was likely to remain stable indefinitely - 400 USD a month. Even though I currently make over $10k. Working for a living is very close to not living at all.

5000 per month after tax

500-700 USD a month. Quite obviously not based in the US, but that much would be more than enough to maintain my cost of living.

well, I'm from a third world country. 1000$ should be enough for me so that I can focus on things I love to do

1500 after tax if there's potential for future growth that can be accelerated by quitting said day job.

I'll go first: For me, my needs aren't that much, I would be happy with $2000/month.

I jumped from freelancing to full-time on my startup when I hit $2k/month.

About $2500 per month after taxes

$2000 per month I think!

1500 per month pretax