When your players finish an adventure, I’m willing to bet they usually want to know what they missed. Should you tell them?
Absolutely! Based on my experience as a GM and a player, here’s why I think this is a good thing to do.
As I usually do, I’m going to assume that you don’t have a dysfunctional group — the kind of group, for example, that would insist on having their PCs return to the things they missed, even if doing so was detrimental to the game.
You should tell your players what they missed because…
As a player, it’s just nice to know. At the most basic level, many players just enjoy knowing what’s going on in the game world.
It conveys an enjoyable impression of complexity. Knowing that there’s stuff in the wings that requires special effort to find tells your players that the game isn’t on rails.
Your players learn what to watch out for. Knowing what they missed may help your players catch more details next time.
It lets your players know where the bar is. Some players really like finding every last morsel of stuff (magic items, clues, bits of info, etc.), and seeing what they missed gives them something to strive for next time.
What other pluses are there to sharing this kind of meta-information with your players? I couldn’t think of any minuses — am I forgetting something?