This is a self-management issue. How much sleep do you need to be effective and how much are you running on?
Just interested as I tend to burn time I should be asleep with other activities at home - cause I'm there so little I have a tough time facing 2h with my family and then off to bed.
For me, I need 7-8 consistently yet average around 6h, leaving me fatigued and less productive at work. I've recently read Saddam Hussein ran on 4h whilst in power. Take from that what you will!