What’s the deal with section breaks?

editing, writing

I’ve been thinking about when it’s appropriate to use a section break in the middle of a story. When I asked a friend, who writes fiction, he told me he uses one when he changes point of view, location, or when he wants to emphasize that two ideas are both key—this is important and this is also important. I tend to overuse section breaks in my nonfiction, probably so I don’t have to think carefully about transitions. Too many section breaks and you get a story that feels fragmented, but breaks in just the right spot can be dynamic and powerful.

Do you use section breaks? How often, and why?