"A lot of entrepreneurs have diluted themselves to think that discipline is working all of the waking hours they have... That is absolutely sloppy work habits when you just let it all bleed in… What's worth spending my time on?" [Link at quote] - David Heinemeier Hansson
"You could work 24 hours a day and there would still be more work."
"Don't think about it as giving something up… Think about it as investing in a sustainable way that will carry you on for more than just the next few months or years."