Oh, okay, maybe not that last one.
My writing schedule is "whenever my mind can settle," which is first-ish thing in the morning and again in the late afternoon/evening. There's a ritual involving dog care and coffee that has to happen before writing or I end up with 60lbs of wriggling fur all up in my personal space. I don't do late night writing sprints because my brain is pudding by then. If real-world stuff has to happen, then it has to happen before noon so I can hit the mental pocket in the second window of productivity.
I like to get my analytical stuff done in the morning (that includes editing, reviewing marketing, budgeting, etc). I do my best creative stuff in the evening (drafting, ad development, social media, etc.). I take a break every two hours at the dog's insistence (plus, it's good for that whole "don't be too sedentary lest pulmonary embolisms" thing). I do this 7-days a week, 10 months a year. Twice a year, I schedule 30-day no-writing vacations (except for this blog, obvi.).
I am a hardcore creature of habit, so anything that interrupts THE PLAN OF THE DAY will have me shifting from Smeagol to Gollum in a nanosecond.
My motto: Spontinantiy is fine, as long as it's planned.