Hiring someone who doesn't work out is unbelievably expensive. It can be a disaster for your team.

When we hire someone, we have no way of knowing if they'll be the life-long learner type who will aggressively consume new knowledge and learn as much as they possibly can. In other words, we have no way of knowing if we can effectively train them, and it's crazy expensive if we can't.

We've tried to hire 1 or 2 of them as interns, but usually they're not interested in being interns.