Garen and Darius

I can't speak for Darius, but for Garen there is no single best build. You have to build reactively against what your opponent is doing.

That said I've had luck with Sterak's Gage, Infinity Edge, some resistances focused on the enemy threats, and one more offensive item based on what I need (Statikk for more crit, Mortal Reminder for armor pen/heal reduction, Guardian Angel for more raw damage with a bit of defense, and Ghostblade for speed).

I've been having some decent luck with Fleet Footwork, but my early damage is worse off and farming under tower requires a bit more effort. Some other Garen mains I respect recommend Phase Rush, and Grasp of the Undying is simply a safe bet if you don't know what else to do.

Again I can't stress enough that it's all relative to the matchup you're having. A damage/pen Grasp focused build is better when laning against Yorick, while crit and Fleet Footwork can be great in a non-burst ranged matchup. You need to experiment with what works best for you to figure out what actually matches your playstyle.

Also there's the BC into full tank Grasp build that makes you a decent damage soak, but to me that's a cowardly build that says "I don't know how to use this champion to his full potential, please carry me".

My General Build for Darius

I take Phase Rush

I usually take or + + or or or or for Garen.

this is part about what i love about playing garen.

you can build whatever the fuck you want on him as long as youre generally still going into a bruiser build.

what youre building for offensive items changes from game to game depending on yours and the enemy teamcomp. same goes for defensive items actually.

even how far youre going into offense or defense can change from game to game.