One question, answered from the books
What is tempo in League of Legends?
Tempo is usable time. Every fast clear, every skipped death, every reset at the right moment hands you seconds in which you can act and your opponent cannot answer. That is the whole resource. Gold and levels are how you win fights; tempo is how you get to choose which fights happen. The catch is that tempo expires: seconds you do not spend on a named play are simply gone. A fast clear that ends with you hovering mid is not tempo, it is motion, and the map cannot tell the difference between motion and absence.
The decision, as a picture
What it looks like in a real game
Two junglers finish their clears at the same second. One hovers mid for fifteen seconds waiting for a play to appear; nothing does, and he starts his second clear late. The other places a deep ward on the enemy blue, resets, and is standing at the Dragon pit with priority when the timer hits. Same clear speed. Different game. The difference was never mechanics.
The concept: The Tempo Trap
The Tempo Jungler names the leak most junglers cannot see in their own play: time spent hovering that produces nothing. The test is brutal and simple, if you cannot name the play you are executing, you are in the trap.
"Tempo is the true currency of jungle"
"But potential that never converts is just time spent."