Tim Ferriss's interview with Seth Godin about the ways ideas spread, marketing, strategic quitting, leadership, and challenging the status quo was one of the best interviews I've heard. It is a powerful combination of informative, helpful, and wise, which is nothing short of what I expect from a 17-time bestselling author with the top marketing blog on the internet (seriously, it's the first link to pop up if you Google "Seth").
While I could go off on a large tangent about everything I learned in this interview, I don't want to spoil it for you. I'd like to point out one small part in particular that agrees with something I've been pondering lately.
Tim asks Godin about his writing warmup as well as the times of the day Godin typically prefers to write. Godin responds with the story of Stephen King's Pencil, in which one writer at a writers conference inevitably asks Stephen King, "Stephen King, you are one of the most successful, revered writers of your generation. What kind of pencil do you use?" Godin proceeds to explain that this doesn't matter, because it's a way to hide. Tying this back to Tim's original question, Godin elaborates on why it is an uninteresting question because there is no correlation that he's ever encountered between how writers write and how good their work is.
I agree with Godin and feel very strongly that this principle also extends outside the realm of writers. It's easy to irrationally assume that doing something one way is the best way, just because someone we know who is great at that activity does it that particular way. We have to keep in mind that productivity and effectiveness are artistries that must agree with our own tendencies and idiosyncrasies. Hence, there is no "one size fits all" for the optimal warmup or time of day to work, and you should do what works best for you.