Well, is it?
I had a Wii before, and the disc was perfectly fine after being inside the system for ages, but I AM kinda concerned about the PS4, because for my Last of Us Remastered Disc, I put it in and never took it out until I was done with the game. When I took it out, the back of the disc looks wierd? I don't exactly know how to describe, but it just wasn't clear as usually. But after a day inside the disc-box, it became normal. I never checked if this happened for my other games xD but all of my discs are still alright.
Is it alright to leave the game disc inside the system?