Most dreams today don’t have significant meaning. However many times they reveal subconcious worries and thoughts. A few months after a very traumatic incident happened in my commuinty i had a VERY frightening dream. I was soo shaken up and asked someone reliable about it. He confirmed that because i was so effected by the incident although i’m not consiously thinking of it every day, deep inside i was, and hence i had a very similar incident in my dream.
There is such a thing as “hafaras cholom” or something like that. if someone dreamt the same exact thing over, and a few other requirements, they have 3 rabbeim or something… and they’re mafir the dream. i don’t know the details but something like that.
I know of someone who remembered all their dreams and would write them down. Years later, after a few of them became true they burned the book.