One word: resourcefulness.
My faculty’s building is open 24/7. Sometimes, homeless people sleep in here. That’s smart.
Who’s even smarter, however, is the one guy who comes into the study room, every night at around 10 pm and collects all the deposit bottles the students have left throughout the day. Him I’d give money.

Collecting returnable bottles is huge in Germany and quite frequently, you’ll find homeless people treating it like a job. I estimate you can make 10–30 € a day with it.
Just the other day I saw a poster here in Munich, campaigning for people to put their empty bottles next to the trash can, instead of just throwing them away.
That way, people can collect them in dignity – and not get sued for fishing around in the trash (yes, this happens).

They even install boxes, so you can drop your bottles for others to collect them.

Given their situation, you’d think all homeless people are resourceful. But there have been incidents in my home town where people collect their welfare money, walk out of that building and then hail a cab to the next liquor store.
I’m young and conservative. I feel like my perspective on this is just beginning to change. I can see how age makes us more wise and compassionate in this regard. I’ll get there.
For now, I’m settling for resourcefulness.
PS: I once tried to give homeless people fruit. It was a challenge for me. One guy wouldn’t take a banana. Regardless of exactly how useful it might have been, I think that shows a lot about how willing you are to work with what you get too.