A-roll at 24 or 30, B-roll at 60, and almost never 240
'Less than 3% of the total videos' need 120 or 240fps.
The frame-rate decision collapses into two buckets. A-roll - the main thread, a piece to camera, an interview, a reel - is shot at 24 or 30 because it should move the way life moves. B-roll, the supporting and cutaway footage, is shot at 60 so it can be slowed smoothly when the edit wants it. Extreme rates are reserved: 'doing a cannonball into a lake or a dirt bike riding through a puddle, that I really just want to slow down as much as possible, that's when I'll use those frame rates.' Shooting everyday walking-and-talking at 240 makes the video boringly slow and eats storage for nothing.
Two defaults replace a decision you would otherwise make badly on every shot.