Nothing Much, Might As Well Spray.
My mom has been using WD-40 multipurpose at the recommendation of a visiting tailor machine technician. Since then, she has been using it everywhere when she heard creaking sound. Door, gate, tailor machine, power tool etc, you name it. I even believe if she owns a workshop garage, she would oiled up/sprayed everything. So here, I am attempting to keep the story simple, short, concise, as sometimes it becomes second nature to just spray without much thoughts. In conclusion, when stuffs creak, you might as well spray.