I've never experienced writer's block. Possibly this is because I always have at least three major writing projects underway. Usually, the three break down this way. One is in the final editing/revision stage. In the second I'm writing a first draft and the third I'm collecting ideas prior to starting the story design. If I'm working on one of the three and my mind is a blank, I put that project away and move to one of the other two. After I while, I can return to the first one and make progress on it.