where does mentoring pay off the most?

I've written before about how much I like informally mentoring people, and it's generally an instinct that kicks in when I spot someone of a particular profile: young/relatively new to the work world, smart, motivated, and promising but inexperienced. And it seems obvious why -- their talents seem worth investing the time to give them some extra guidance and attention, to help them really flourish. And often they don't yet know that there's something special about them, and it's rewarding to help them spot and harness it.

But it occurs to me to wonder if it wouldn't actually be better to apply that kind of time and attention to a different type of person instead -- the struggling rather than the obviously promising.

Do we seek out those with star potential because they'll benefit the most from our help -- or is it possible that it's actually less about that and more because we like to see ourselves in them, or that it's so gratifying to watch them blossom and feel we played a role in their success? Maybe we'd actually have a more significant impact if we made that kind of time investment with someone who doesn't have obvious star potential, someone who doesn't appear to be a natural candidate for grooming.

After all, the clearly promising ones are more likely to find their way regardless of our help, although perhaps our help gets them there faster or more smoothly. It's the not-so-obvious candidates where mentoring and extra attention might really make the decisive difference.

I suspect this isn't a novel thought at all to many people, but it was a semi-epiphany for me.