Most businesses get hiring wrong by hiring too fast (filling roles before defining them, taking first reasonable candidate, missing red flags). And they keep poor hires too long (sunk cost, hope they'll improve). The reverse — slow hire, fast separation — works better.
What 'slow hire' means
Define role specifically before posting. Interview 5+ candidates minimum. Reference checks done thoroughly. Trial work where possible. Better to leave role open another month than make bad hire.
What 'fire fast' means
If by 90 days a hire clearly isn't right, end the employment. Don't drag it to 6 months hoping for change. Damage to team, to your time, and to the person themselves compounds with delay.
Hiring decisions are among the highest-leverage business decisions. The patience required to do them well almost always pays back.