7-8 hours every night.
If I sleep 4 to 5 hours I am equally as productive as when I sleep 7 to 8 hours however I can only keep that up for a couple days, before loss of productivity.
Yeah pretty much this; on average I sleep 7 hours, but I can go in to "overdrive" mode and sleep less hours while not losing focus/drive to produce, this only lasts 2 days though, after that I really need to "recalibrate"