But, I don't see that unproductive poking as anything other than part of the writing process. I poke around, see what happens, sometimes spend days scribbling in a file block before I type again. . .
So, if it's not flowing that day, go and do something else that is part of the process. Think about a character arc, write out a time line, go and read something that you think might help the block. If it's part of the process, that's still writing time to me. And that's sort of what I meant about taking a pragmatic approach; that if it's the time you've set aside to write, then you should. It just doesn't neccessarily have to be three hours at a keyboard.
Beautifully put, Springs