Actually, this phrase is wrong. It can hurt to ask. Sometimes it can hurt bad.
When you ask too soon in a relationship, you can appear greedy or needy. When you ask too late, you can appear slack or, worse, disinterested. Asking for something that a donor has no interest in can suggest you haven’t been listening. And having the wrong person involved in the ask can suggest you don’t understand the importance of social protocol and status.
Yes, in general, you need to ask in order to get. But “when,” “who,” and “for what purposes” all play key roles in how successful (or destructive) your request will be. Only when you have a certain measure of familiarity, understanding, awareness, and trust in the relationship can you say, “it never hurts to ask.” And even then, it never hurts to proceed with great thought and care.