Usually, you want to look at the top card in your Life area, and if its a useful trigger, youll keep it at the top so that when your opponent damages your Leader, you can activate it
To make a concrete comparison, I believe Turret Ogre is better than Dreadhorde Twins in most red decks
Magic: The Gathering Arena is free to download for PC.
In Saga draft, it was a neat trick with Horseshoe Crab, creating what was known as "the Machine Gun." In Odyssey Block, it was said that if you didn't have at least one Psionic Gift in your white-blue deck, you didn't have a good white-blue deck
It's also a key component of infinite mana combos in Commander, where it converts an arbitrary stack of mana into lethal damage