As someone who's in school for film editing right now, we're told that the general rule of thumb is to follow the "rule of three" - that is, it's generally most aesthetically pleasing when things happen in threes.

Take the Falcon approach to Yavin IV - in the 1977 cut, you have three (I think) shots of it approaching in space. Once it's in the atmosphere, it's considered a different location, so the rule resets.

However, we're also taught that such "rules" are guidelines, not rules, and things such as this are more governed by what feels right, or good, than the numbers themselves.

But once you start thinking about the "rule of three," you'll see it everywhere, especially in editing.

--edit--

And TheBoost gave a much better answer than I - it has to serve the story first, above all else.