Mentor Trait?
One of the traits you can buy with aspiration points is Mentor. Apparently it lets your sims mentor other sims when they reach level 10 of a career, but my sims have always been able to do that anyway...
Forum Discussion
The Mentor rewards trait seemed useless to me at first too, but it actually does boost the skill gain even more when mentoring sims which I find really useful with getting parents to mentor their kids.
