Tips on making a snazzy storyboard

Things I learned:

• Avoid drawing a flat stage but instead draw grids and vanishing points because it adds more depth and make your scenes look more interesting 
• Give your shots some life. The article says if there is a noise off screen you should draw your character maybe looking towards it and drawing an effect that'll indicate a noise coming from that direction
• Labeling your characters makes it a lot easier when making a storyboard especially if you're dealing with multiple characters in one scene

My Opinion:

• I like that the author tells us why they like making a storyboard and touches on the subject of seeing your imagination come alive.
• They also tell us why making a storyboard is helpful because you can look at it after and see if there's anything that can be improved 

My question is how long does it take to finish the storyboard and do they draw the entire movie or only draw the most important things and leave out smaller scenes to just be done on its own