I think this is predicated on the idea of replacing an employee who leaves of their own accord, that you would have preferred to hold onto. Not of one you let g

I think this is predicated on the idea of replacing an employee who leaves of their own accord, that you would have preferred to hold onto. Not of one you let go, or are glad to see leave. Basically, just the employees who are worth the amount you are paying them, or more; not those who are worth less.