Short post for today. That's ok, right?
Often at the end of a campaign your players may not be quite finished with their characters. Sure, the game is done and the story arcs have been completed but there is still something missing: closure. Closure, or the lack thereof, is often what you experience at the end of a tale when all the loose ends are wrapped up. Some movies, like Warrior (fun movie if you like fighting/sports movies) have zero closure in them and it can leave you hanging. Other movies, like the Return of the King, can sometimes provide an over abundance of closure. Regardless of how it is treated though, closure is important.
How much? Well, a lot of the rage towards Bioware with the original - and extended - Mass Effect 3 endings was the lack of closure. Through the course of the story/game your players have grown close to their characters. When the game is over, they want to know what happens with the characters. Do they live happily ever after? Do they die a miserable death shortly after their grand achievement? That is closure, and it is a good thing to give.
Personally, I do it with epilogues. When a game is done I give the players almost total free reign to write their epilogues. I retain veto power for things that just couldn't/wouldn't happen in the world (i.e. "I make all the Drow lawful good!") but for the most part this isn't a problem. The reason why? Because the player isn't looking to tack on additional merits to their character, they're just trying to answer the final "and then what happened."
Most often when I do this I get responses like "my character will serve with the Imperial Legion until his fifties, then retire back home with his wife and spend the rest of his days living the quiet life, aside from the occasional time he is asked for advice on something." or "My character climbs a mountan and forms a school to teach the style of swordsmanship that they have developed over the course of their life."
Whatever way it happens, it is generally something deeply personal to the player and the character. You should give it a shot. Your players may amaze you with how much depth they saw/put into a character that otherwise just seemed like a cookie cutter fighter.