After all sorts of various schedules over the years, have had to settle on 8hrs, even though I can get by on 6.5-7hr. In bed by 10pm, up @ 6am (MST). Really helps that my wife is on same sleep cycle. Actively trade futures (index/currency) from 6-615am until 2pm. Accounting/data downloads until 215-230pm. Eat solid late lunch, then 20min power nap followed up by 45 min hard workout session. Back at house by 4pm, research until ~6pm dinner when wife returns home from work. Dinner at least 3-4hrs before bed seems to help me quite a bit. If post-session work load is light, will just eat and head out for 18-holes or get 5-7 ski runs (Colorado ftw). Typically do this at least once a week...helps prevent burn-out, which can sometimes lead to sleep difficulty.
If one wants to survive over the long haul as an independent, def recommend appreciating importance of sleep, eating well, taking time off, and physical activity. You hear the party late/work 80hr wk war stories, it's total nonsense once you get past mid-20's/single life, are not working with a team, and have to be razor sharp 230+ sessions a yr. Strict discipline is name of the game, I would wager most genuinely learn this too late. FWIW, I'm in the 30-35 age bracket.
OP: I'd stick to the 8hrs if that is your natural cycle. If there is room to improve, work on efficiency with your time during the day. My wife and her old boss did polyphasic (clinical research engineers/flexible schedule), somewhat works for him, def not for her. It's hit or miss with many.
