Sometimes something sticks out, like a Chekhov's gun, and you're just waiting for it to make it's way back into the story. Not all of the small details, obviously. But you can pick up some things on a single read through that you expect to come back into play.. even if you have a horrible memory.

Yeah the goodies only shows when you read it a second time, especially when the manga is like bi-monthly or monthly, no one gonna remember something 10 chapters away which could be anything between 5 to 10 months.

Maybe, but then I've got better things to do than reread or rewatch things...