i know a couple of directors who do a storyboard video with friends on a small canon....
then edit it....
now you have the complete movie in a really rough version and can see where the problems are (pacing, staging, storytelling...of course you never judge the perfomance of the actors)
then commonly they rewrite parts of the scripts...make scenes shorter, longer, rearrange scenes, add shots, delete shots, add/change camera movement) etc.
its a great way to find out if what you have in your head is really understandable to the audience.
this is another underreted part in film making.
every director get sleepless nights if it happens that what was in his mind doesnt transport to the screen.
here it get popular after carlitos way and the shoot out in the barber shop. (it had a problem with pacing) de palma just shot some more shots and changed the place of some shots...the sequence is now longer but felt shorter than the original one.
eidt: previz are pretty common today i guess, but if you cant afford a 3d storyboard artist, you get creative.