I play a lot of board games. And I own a lot of board games. Not all of my games get played very much, so I like to track each play and over time see which games are forgotten gems or which games I'd be best to just trade away.

In the board game community, you might come across people talking about the "Friendless" metric of their collection. It's a totally made up measurement, invented by a person with the user name Friendless. In that way, it's like the Elo rating in chess and other games. I find it's useful to know when I'm "done" with something that doesn't really have an end, like playing board games. You can always play one more game.

Friendless hypothesized that if you play a game 10 times, you've gained 90% of its remaining utility. So after 10 plays, you consumed 90% of the game play that game provides. After another 10 plays, you're at 99%. By the time you reach 30 plays, you've consumed 99.9% of the game.

You can do the same with games. Maybe the number of plays changes a bit. Maybe it's not the number of plays, but the number of hours. I would say that games of Civ are like games of any other board game: 10 = 90% utility gained. Matches in COD, probably not the same.