Here's one way to think of it. Suppose you're working on a new product, and you have to decide whether to spend 30 hrs or 60 hrs / week on it, over the next two years.<p>If the difference is between failure in the first case, and success in the second case, then it's either a bad product, or you're bad at planning. If you work half as much, then maybe it will have less features, but a good product should still be viable. And everyone knows predicting how your software will adhere to a schedule is impossible, so the chances are good you wouldn't even get it to work at 60 hrs/wk.<p>Obviously, an order of magnitude difference in effort should produce a qualitative difference in your product. You can't replace ten good programmers' time with just one.<p>But picking startup ideas that require you to be working 80 hours a week, is just bad planning -- it's waaaay too risky. When you live in a first world country, and are doing this out of choice (not survival), it's insane to sacrifice your health like that.<p>If an idea is really good and really sustainable, truly a good business idea, then there are much healthier ways of finding success than working 80 hours weeks -- finding partners, networking better to get investment, etc.<p>I'm not advocating anything silly like a 4-hour workweek. I'm just advocating realistic expectations, realistic risk management, and realistic work-life balance.<p>You might get hit by a car two years from now. You don't want to have neglected all the wonderful things in life, like relationships and experiences with people, in exclusive pursuit of a startup over those two years. Even <i>not</i> getting hit by a car, there's a large chance your startup will fail. Don't throw away your life in complete pursuit of a single thing -- healthy balance is key.