The 2nd Cut is for Rhythm
The first cut is for assembly. To get the material on the timeline, in an order.
The second cut is to smooth the assembly — into a natural, organic, breathing rhythm.
That's why you can't realistically finish a good movie 24 hours before its presentation.
This is for the procrastinating filmmaker. For people who wait till the last minute.
Note that "the last minute" should be at least 24 hours before the project is due.
Your eyes need time to refresh, your brain needs time to process the decisions you're making. Trust me. If you're a film student or cranking movie-products out for clients, and you get like me (in spells of procrastination), you're definitely going to want those extra 24 hours.
The first cut is supposed to be clunky. It's not supposed to be good.
A movie usually takes 6-9 cuts before it's any good.
The first cut is more like factory work than fine art. It's about chopping & placing & moving on.
The second cut is your chance to see the movie's assembly, and now you can begin thinking about the graceful stuff like rhythm. It'll be obvious what needs to slow down, speed up, be removed, or added.
I love making a lot of movies fast — so I (try to) give myself 24 hours before polishing.