Planning a 90-second film on index cards

Before I draw a storyboard I write every scene on an index card and lay the cards out in a row (sample note).
A 90-second film has room for twelve to fifteen scenes. If the cards for the first half already fill the table, the script is too long, and it is much cheaper to find that out with cards than with animation.
Clients are welcome to join this step on a video call. Moving a card takes a second.