I've been living and working in NYC for several years now and my expereince with this has varied. It depends on what industry you're looking at. Making websites or apps for marketing and advertising firms will always demand more of your time per week. Startups expect a developer to act like a founder by living and breathing their work. Doing the same work for a financial firm will not so much (although the full timers at my last job were expected to work 10 hr days). I'm currently at a big bank and my hours are regular and with reasonable deadlines.