The use of terms like "sweetie," "darling," and "babe" as endearing or affectionate nicknames is generally subjective and can vary based on cultural norms, regional differences, and individual preferences. There isn't a specific age when someone universally stops being called these terms, as it depends on the context and the relationship between the people involved.
In informal or familiar settings, these terms of endearment might be used between close friends or family members, regardless of age. However, in more formal or professional settings, it's generally considered more appropriate to use formal names or titles.
As people age, they might find these terms less commonly used towards them, especially in professional environments or by people they don't have a close relationship with. It's always best to be sensitive to others' preferences and use terms of endearment only when you are confident that the person is comfortable with it. If in doubt, it's better to use more neutral language until you become familiar with the other person's preferences.