When you see someone who seems to need help, or asks for a favor, for what reasons might you hesitate? Yes, there are some areas you need to be discerning about. For instance, if someone on the street asks for some money, you probably usually shouldn't just hand them money, because the truth is, they might spend it on alcohol or drugs, & that won't help them. But what is okay to do? It's up to you & the leading of your heart, but I'm of the impression that giving someone some food to eat or gas for their car - for some examples - isn't going to hurt anything. But what if it's a scam & they don't really need your help, or what if they're bad people & helping them might hurt someone else later on?
The first example that comes to my mind is Clark Kent (a fictional character). Some of the people he saved turned out to be bad people, & if he had not saved them some other people would not have been hurt later, but at the time he saved them he didn't know that. He came to the realization that it was his responsibility to save anyone he had the opportunity to save - whom to save & not save was not his call. We don't have superpowers like Clark Kent, but I think the principle can apply to us, too.
Maybe you think, "I have needs, too; why should I help someone else?" Sometimes that's a valid argument, & it's no reason to feel guilty if you're unable to give; but the widow in Mark 12:41-43 & Luke 21:1-3 who gave everything she had comes to mind. If you know Jesus as your Savior, just do what the Holy Spirit leads you to do.