It's no surprise to me that street people start reconsidering their life choices in their mid-thirties. A flash of introspection happens at the magical turning from 29 to 30, but quickly fades. Later on, between 34 and 40, people start wondering if this is going to be it. A decade of heavy drinking, hard partying, camping on the streets, traveling by freight-train, and harassment by the cops: it's all a blast until that one day when you wake up bruised and vomit-covered at 35, and you wonder if there might be more to life.
In my years around this scene, all the major life decisions have happened during this vulnerable moment of conversion. When friends I know decided to wise up (and sober-up) and move in out of the park (often to live with us), it was often on or near a birthday in their mid-30's. That's when the contemplation moved to a deeper level . . . as if, somehow, the constant party had worn thin and they could picture, for the first time, the prospect of growing old this way.
It could easily be a mantra that we invest our lives in twenty-somethings so that they trust us when they become thirty-somethings.