I'm 20 years removed from college and I still have the old classic dream where I forget to go to class for the entire semester, fail, and completely screw my entire GPA up. So ... it takes awhile.
I'm 14 months removed from booze, so I still have the drinking dream occasionally. I actually love this dream, because every single time, I drink and feel absolutely terrible because I've screwed my sobriety up, then I wake up in total relief that it was only a dream. For me, those dreams reinforce the importance of my sobriety and I welcome them.