What are the primary sources of janitor attrition? Frustration, loss of interest in 4chan, IRL interference?

By this I mean either leaving the team, or else steadily increasing inactivity over time.

I tentatively invite people to speak both about their own cases as well as what they have observed in others. As I understand it, nobody can see who you are here unless they have admin tools on, so I am confident that nobody will be called to answer before the commissariat for anything they might say.