Are you asking if people are full-time ABs? I would say I am but not in the way you're posing the question. The "A" stands for "Adult", so there's no conflict in managing myself in the adult world while having that as part of my internal workings. I'd be bored to tears stuck as a baby all the time. I think the good stuff is in finding fun and effective ways to balance the urge and responsibilities so both are satisfied.
Do you mean about what do you do when you're not in little side? Well, I'm doing so much things of works like geocacher, lecture assistant, engineer and also student at university, sometimes I spend my little time at my little side when I'm doing nothing. My thought was same like Trevor says.
Working, playing outside, video games, spending time with my fiance. Honestly my little side takes up only a little bit of my time, but it's fun when I get it.