decide you like a game
1 play
decide this game is one of your favorite games
Interestingly, compared to everyone else who has answered so far and said it took a long time, I can decide a game is a favourite very quickly. If the initial plays are amazing, it’s in.
decide that a game is not for you
Also 1 play, although if I’ve spent money I’ll keep trying in the hope I like it more. That doesn’t usually work.
decide that a game has to leave your collection
That’s determined by time UNplayed on the shelf 