Is there a word or phrase for doing a favour or helping someone because you are in a better position than they are to get it done?
For example, it would take me a lot longer to herd some cattle than it would for a cowboy to, so this word/phrase would apply if I asked the cowboy to help me (but not if I asked someone equally or less capable than myself). Or, for instance, I might walk to the shop for my grandmother because she's elderly, but not for my brother because I'm in no better position to that than he is.
Is there a phrase to summarise this kind of situation?