Someone doing it for experience will do it just for that, so junior engineers are ok. But don’t expect someone with 30 years experience building companies and complex tech and kids in college to come and take you to the next level. Taking a 70% haircut for nothing isn’t plausible. And you don’t need to sleep in the office and kill yourself to build amazing software fast and grow a business. Only kids getting started think that works. After multiple 36+12 stunts in my first startup, which was in fact wildly successful, I realized that after 10 hours I wasn’t doing anything valuable. I was spinning my wheels and burning myself out. Now I can do much more in 6 hours of work a day.

I mean hell, you could be part of the magic sauce that helps a new startup grow into something really promising, but until the higher-ups recognize you and truly respect you, you'll probably just get shoved aside at some point, because politics or whatever other change happens during the growth. And the only thing that reflects respect is 1. a meaningful equity percentage and 2. guarantee that you won't be forced to give up the stake because of some exercise deadline after you leave.