Around 9. But just a number doesn't say enough by far. I've been through about one year with only 7 hours and have been perfectly fine - I used to wake up by my

Around 9. But just a number doesn't say enough by far. I've been through about one year with only 7 hours and have been perfectly fine - I used to wake up by myself because I had something exciting to do. Most of the time though waking up an hour earlier will cost me a full day of drowsiness. Also this, about 2-3 hours. But freelancing, so it's ok. http://en.wikipedia.org/wiki/Delayed_sleep_phase_syndrome http://en.wikipedia.org/wiki/Delayed_sleep_phase_syndrome