The longest one I ever did (playing every game) was on season ticket baseball when I played with the Mets and got through about five seasons. Generally I tend to end up starting a few different one's without really seeing them through. I always prefer to play out each game but the downside is it takes a long time to get through a season and my mind turns to that other thing I was going to try...
At the moment I'm playing as the current Orioles and after a five game winning streak I've got them to 17-16!! I think I should just leave it there before things turn ugly.