I have a friend who plays Nancy Drew games only once, and once completed it, never returns to play it again.
I'm different. I replay Nancy Drew games over and over and over again. XD I really like playing it in (almost) different sequences, exploring rooms at different times or try to get different answers from characters. I remember replaying The Final Scene just to try racing against the kidnapper's moves when he/she takes Maya around the building. I'd always try to get to her hiding location before the culprit did.
In later games, it's fun to replay in attempts to get all of the end-game meta awards and trophies, as well as purchase all foods and souvenirs in the processes.
Do you replay Nancy Drew games? What do you do differently each time you play them?