Stoic advice: what are the limits of our ethical duties?

M. writes: How does a Stoic judge the limits of what they ought to do in a situation where theoretically they could have a great influence if they used all their resources or even sacrificed themselves? Any of us could intervene to greatly improve the life of a person in crisis, and such people aren’t hard to find. But how should that be weighed against however one would prefer to use one’s