Depends on the game. But I like games with tons of replay value. Whether it's 10 min matches of COD or a big RPG, I like getting good fun and value out of it. I'd take a repetitive shooter or sports or Diablo clicker over a canned game you can beat in a weekend.
But like all games, it gets to a point of burn out. A good COD I can play for 100s of hours. I think my highest COD game back in 360 days was like 20 days, so that's 500 hours! Then I had enough and move on. But for an RPG I still like 50+ hours. Beat the game, roam around to do more random quests and then similarly, I had enough and quit.
But if it's a cheap indie game where the gameplay loop dies fast, 10-20 hours is good enough.
I dont play typical 8-10 SP focused games anymore. I dont think I've played one of those kinds of games since 360.