PS4 owners may want to upgrade their hard drives. Sony has confirmed that every game requires an installation, including games purchased at retail. The mandatory installation requirement is similar to Xbox One.
A new FAQ reveals that, "all PS4 Blu-ray Disc games must be cached to the hard drive to ensure a smooth gaming experience. However, certain titles may not require you to wait for the game data to be fully cached before starting gameplay. In order to start playing disc-based games, users will need to insert the game disc into PS4 just like on the PS3 system."