I don't play most videogames all the way through more than once. Not when there are tons of options available to me, or I know I could have achieved a different ending, or even when there's some super-cool character or pathway just waiting to be unlocked. I also don't often fully re-read novels, and if I completely re-watch a movie it is a significant thing. When I tell fellow nerds that I've seen Monty Python and the Holy Grail six times all the way through, for example, it fails to impress. "Pfft," they say. "I've probably seen it sixty times." This irks me to no end. It's one thing if you're an academic conducting a comprehensive study. Otherwise, why does it matter how many times you were exposed to something if your one experience was so meaningful?
It's no secret that players are often given incentives to play over and over again.
It's no secret that players are often given incentives to play over and over again. We welcome it. At this point, we not only expect to spend 30-40 hours with a hot new release, but to work through it more than once, usually in the hopes of earning alternate content. In spite of that, I don't think it's bad or "a waste" to have one defining run through a story-driven game and then put it aside, especially if that run takes ages to complete. After all, videogames have always depended on user choice, and what better way to demonstrate the importance of your choice than by living with what you didn't choose? Yes, there are those that prefer to stay in their virtual worlds indefinitely, but for most of us ennui has a way of setting in sooner or later. Just take a gander at the forum posts of folks who became bored with Skyrim and the like after the big quests were finished. Knowing there are things you never explored can enhance your own interaction.
It's true that there was a time when not knowing what to do in a game could be fatal. Constantly retracing your steps or restarting entirely used to be essential to figuring out the tricks of survival in order to get the single "good ending." Fortunately we seem to finally be at a point where most games have some way to keep you from getting totally stuck, and we should take advantage of that. If you know you won't screw yourself over because of some irretrievable McGuffin you forgot to pick up hours ago, you should be free to play without guilt. You might not get every point or power-up, but a well-designed game should at least give you the chance to have a full and satisfying experience the first time.
This approach doesn't mean you have to forget a game exists after you're done. It can be fun to introduce a title you've already conquered to someone else to either watch them play or let them watch you. In that case, though, you're not invalidating your own "first time" so much as absorbing pleasure vampirically from someone else's. After I beat Portal I remember booting it up for my brother and eagerly watching him figure it out, occasionally dropping hints and waiting anxiously for his reaction to the ending. I had no desire to do it again for myself, but I enjoyed witnessing his first experience (which sounds a lot creepier than it was, I swear). It also doesn't mean you can never restore a save to fix a mistake, or even that you can't retry a final sequence to see if you get a better ending if you shoot the bad guy instead of your girlfriend. But once you're done, you're done, and your relationship with that title will never be mine.