If the title didn't make it clear, I'm talking about game you've spent good time with or completed, and enjoyed, and put away for a long time to revisit 'fresh' in the future. The mention of Dr. Chaos for the NES in another topic made me think about this, because I always forget what to do every time I revisit it (which isn't often).
I do this mostly with horror games. Even if I didn't have a ridiculous backlog of games to get to, I'd still only replay horror games several years after my last playthrough. Silent Hill 2 for example is one of my all time favorite games, and probably my number one favorite survival horror title. I've played through it 3 times over the past 15 years. While I never forget the plot, 5 years in between plays is more than enough time for me to forget where everything is, and the solutions to all of the puzzles. It's also long enough time from an earlier playthrough that I can use unlocked items without it feeling tacked on, or like I'm playing through again JUST TO use them, or to try for a different ending. I usually bump the difficulty up a bit, too to keep it fresh.
I've never replayed a Dead Space game, but I remember very little about each game besides how they each began and ended, so when I revisit them, it'll probably be almost as exciting as it was the first time around. As much as I loved Fatal Frame, it's been over a decade since I've played it and I remember almost nothing about the game besides how it's played. I don't recall the story, enemy or boss encounters, or where to go or what to do, so I know that if I revisited it now I would be every bit as creeped out as the first time.
Do you ever shelf games you really love to preserve the experience, even if it means waiting years to enjoy them again?