Squeaky-less joints
I once had a neighbor who had squeaky joints on all of their doors. I remember jumping up scared every time they opened something. It felt like I was living with a ghost in the next-door apartment. Maybe I wouldn’t have been so frightened if they used WD-40.
Lubricating hinges is one of the most conventional uses for WD-40. But it is effective nonetheless. Remember that it may not bother you to have squeaky joints, but you may be frightening your neighbor with the sound.