We don't really know what it is, but it's not a choice. Randomness, boredom, could be anything. People can stay for years or only for a week or two. I don't know what the quickest turn-around is but I wouldn't be surprised if it's only a few days.
I'm not sure I technically count for the club, because I was going to come back to life anyway and I'm gonna do it a few more times. But I think I'm also not the only one who's going to die at least a few times before it sticks. So I guess it's kind of up to everybody in the to decide what counts for the club or not.
But I forgot to say, welcome to Tumbleweed. I'm Sam Winchester.