I once broke down at a major intersection in a dangerous spot, and the homeless people working the corners came out into the intersection, directed traffic, and pushed me to safety in a parking lot. I was out of work several months myself at the time, had no cash, and felt terrible that I couldn't give more than a thank you.
I've also been targeted by the same woman years apart in completely different locations with the same story about being in town for her sister's funeral, her newborn in a hotel with no food, and she needs help.
There are the decent ones who need a leg up, the ones who are seeking to feed addictions, and those who are despicable liars. It's hard to sometimes tell the first two apart, but the third type is easy. I more or less never have cash on me, so not giving to them is usually a default no. When I do, I know which street corners in the area have the honest people who need help. I'll always give cash at Christmas time to whomever is at that one intersection where I broke down years ago. I never give to anyone who corners me at a gas station or grocery store, or to anyone who seems to know where the nearest ATM is located.
Mostly, all my spare money gets allocated to help rescue pets and some children's cancer and hospital funds (my wife's and nephew's histories).