I myself am saving that after I complete the game. In my mind that kind of thing is cool when you realize you didn't see these awesome things before.
Same here OP. I'm not even rushing with my first playthrough. I'm observing every corner and am still missing a few collectables. This is not the type of game where you go where you're supposed to go, you have to explore
Naughty Dog are great artists in the smallest details, literally EVERYWHERE you look there IS something, a poster, rotten wood, a typewriter, you name it and it is there. This is one of the reasons I always love ND's games I try to see as much as possible