Question: We give our ma'aser money to institutions who deal with chessed and Jewish education. However, there are constantly people coming to our door asking for help. What should we do? 

Answer: It is certainly preferable for you to give your ma'aser money (or at least the lion's share of it) to institutions and charities which are worthy and needy from your perspective. At the same time however, if a poor person stops you and asks for help - even if you aren't sure of his genuineness or legitimacy - you should still give something as it is a matter of physical survival. You certainly have the right to refuse help to an institution with which you are not familiar, or whose principles you do not agree with. But in the case of helping an individual whom you don't know, you must give something, though it need not be more than a few shekels.